A century of hair shows how lead exposure collapsed

Perpetual Student · Saturday at 2:15 PM

A century of hair shows how lead exposure collapsed

For decades, Americans were surrounded by lead from car exhaust, factories, paint, and even drinking water, often without realizing the damage it caused. By analyzing hair samples preserved across generations, scientists uncovered a striking record of how exposure soared before environmental...

www.sciencedaily.com

Lead is a toxic metal that builds up in the body over time and has been linked to learning and developmental problems in children.

Scientists at the University of Utah analyzed hair samples and discovered steep declines in lead levels going back more than a century. Their results show a clear downward trend beginning after environmental regulations were introduced.

"We have hair samples spanning about 100 years. And back when the regulations were absent, the lead levels were about 100 times higher than they are after the regulations."

The study, published in PNAS, highlights how environmental protections have shaped public health outcomes. It also points out that some lead regulations are now being weakened by the Trump administration as part of a broader effort to loosen environmental safeguards.

d taylor · Saturday at 2:22 PM

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But it makes the best oil paint (white)

Aryeh Jay · Saturday at 6:06 PM

d taylor said:
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But it makes the best oil paint (white)

And lead acetate is sweet.

ThatRobGuy · Saturday at 8:43 PM

While it's great that we've reduced lead exposure, the fact that we still have one of the highest chronic disease rates among developed countries would suggest Americans couldn't wait to find other things to poison themselves with to replace lead.

Hoping that in 80 years from now, scientists will be studying hair samples and reporting that the levels of residual microplastics and Chicken McNuggets have gone down.

The study, published in PNAS

dang, that's an unfortunate name for a publication when you read it phonetically...

Chesterton · Saturday at 9:00 PM

Going back 100 years? That's some good science.

Perpetual Student · Sunday at 8:31 AM

ThatRobGuy said:
While it's great that we've reduced lead exposure, the fact that we still have one of the highest chronic disease rates among developed countries would suggest Americans couldn't wait to find other things to poison themselves with to replace lead.

Hoping that in 80 years from now, scientists will be studying hair samples and reporting that the levels of residual microplastics and Chicken McNuggets have gone down.

The fact that the current administration wants to roll back protective regulations, especially on toxic products that affect children is rather worrisome.

ThatRobGuy · Sunday at 9:33 AM

Perpetual Student said:
The fact that the current administration wants to roll back protective regulations, especially on toxic products that affect children is rather worrisome.

In the case of the lead pipe reduction/replacement, if there's a silver lining, it's that the problematic infrastructure has already been replaced in most places.

By current estimates, only 2.8% of homes/buildings are downstream of lead service lines.

Meaning, 97.2% have already corrected the problem. And it's not like the utility companies are going to go into their pockets to dig it all up, find a supplier, and put lead piping back in. (especially when they can run PEX and PVC for $0.75 per foot)

Same goes for the fuel... gas stations aren't going to spend their own money to re-install infrastructure for leaded gasoline.

Tuur · Monday at 3:59 PM

Glad that someone mentioned tetraethyl lead. That was the major source of lead in most of the US environment. Lead paint got a lot of the attention back then, but unless a child ingested it, say by chewing painted wood or dried flakes, it was pretty inert. And while no doubt some children did just that, I don’t think it was as widespread as feared. Tetraethyl lead was everywhere, courtesy of auto exhaust.

Pommer · Monday at 4:16 PM

Tuur said:
Glad that someone mentioned tetraethyl lead. That was the major source of lead in most of the US environment. Lead paint got a lot of the attention back then, but unless a child ingested it, say by chewing painted wood or dried flakes, it was pretty inert. And while no doubt some children did just that, I don’t think it was as widespread as feared. Tetraethyl lead was everywhere, courtesy of auto exhaust.

It “done things” to the Silent and Boomer generations that we cannot even imagine nor throughly comprehend.
Cognitive things.

Tuur · Monday at 5:30 PM

Pommer said:
It “done things” to the Silent and Boomer generations that we cannot even imagine nor throughly comprehend.
Cognitive things.

There's a "lead line": that can show up on the gums at the base of the teeth when there's a high exposure to lead. We knew of it but don't recall seeing it. All that means is exposure was generally less than that needed to form the line, but it's still a quick reference.

Meanwhile, those of us who, as the song Waiting for the Hammer to Fall by Queen put it, "...grew up strong and proud/beneath the shadow of the mushroom cloud" have strontium 90 in our bones, courtesy of above ground nuclear tests.

Then there's arsenic in certain crops, a legacy of when it was used to control bowl weevils.

Tuur · Monday at 5:37 PM

ThatRobGuy said:
In the case of the lead pipe reduction/replacement, if there's a silver lining, it's that the problematic infrastructure has already been replaced in most places.

By current estimates, only 2.8% of homes/buildings are downstream of lead service lines.

Meaning, 97.2% have already corrected the problem. And it's not like the utility companies are going to go into their pockets to dig it all up, find a supplier, and put lead piping back in. (especially when they can run PEX and PVC for $0.75 per foot)

Same goes for the fuel... gas stations aren't going to spend their own money to re-install infrastructure for leaded gasoline.

Lead pipe was perhaps rarer that many think. I once lived in a house built in the 1920s, and it had galvanized pipe. Once source claims it was used for service lines in the US as late as the 1980s, but in the 1960s I was learning to work with galvanized pipe fittings on the farm, and we flared copper pipe and used fittings rather than sweating joints, and by the 1980s was working with PVC

Tuur · Monday at 5:40 PM

Aryeh Jay said:
And lead acetate is sweet.

But paint used lead oxide. Made a white paint that could be used as a base for making other colors. Wouldn't know if it had a taste or not. Titanium oxide seems to have taken the place of lead oxide.

Aryeh Jay · Monday at 5:53 PM

Tuur said:
But paint used lead oxide. Made a white paint that could be used as a base for making other colors. Wouldn't know if it had a taste or not. Titanium oxide seems to have taken the place of lead oxide.

I think I heard that lead based paint chips had a slightly sweet taste years ago, but I could be wrong.

Aryeh Jay · Monday at 5:55 PM

Tuur said:
Then there's arsenic in certain crops, a legacy of when it was used to control bowl weevils.

A lot of rice grown in Arkansas has high arsenic levels because of that.

ThatRobGuy · Monday at 6:07 PM

Tuur said:
Lead pipe was perhaps rarer that many think. I once lived in a house built in the 1920s, and it had galvanized pipe. Once source claims it was used for service lines in the US as late as the 1980s, but in the 1960s I was learning to work with galvanized pipe fittings on the farm, and we flared copper pipe and used fittings rather than sweating joints, and by the 1980s was working with PVC

Actually, you'd be surprised...

Between 1900 and 1950, a lot of the major cities used lead pipes in the service lines.

And while some of the health risks were becoming more apparent before... major drop-offs in usage (and safer replacements) didn't occur until the 70's and 80's.

To put it in perspective, the Safe Water Drinking Act didn't happen until the mid-70's. (and usage with regards to new pipes wasn't effectively banned until 1985-86)

Tuur · Monday at 7:27 PM

ThatRobGuy said:
Actually, you'd be surprised...

Between 1900 and 1950, a lot of the major cities used lead pipes in the service lines.

And while some of the health risks were becoming more apparent before... major drop-offs in usage (and safer replacements) didn't occur until the 70's and 80's.

To put it in perspective, the Safe Water Drinking Act didn't happen until the mid-70's. (and usage with regards to new pipes wasn't effectively banned until 1985-86)

Yet there was the aforementioned house, built in the 1920s, with galvanized pipes. I've seen galvanized copper; thin black plastic that came in rolls and leaked like soaker hose; a composite made out of orange peel that had the longevity a little longer than a paper cone cup; terra cotta drain; cast iron drain; and PVC. I have seen lead in plumbing once: the part that goes from the commode to the sewer line, and that had to be replaced.

This is a rural area. It's possible to make the argument that when people had electricity and water pumps they could have indoor plumbing. That would imply that plumbing installed after that would be more likely be the the latest and greatest, and that happened to be galvanized. But then there's that house built in the 1920s with galvanized pipe. That was at least fifty years before the Safe Water Drinking Act. So why wasn't lead water pipes used there?

That's why I'm skeptical. Water tests show the presence of lead in water in places, but I have to wonder about the age of the pipes. My guess is that any continued lead pipe sales were for repairs and not new installations. Given the aforementioned age of plumbing I've seen, I'm suspecting we're talking about pre-1920s. If that's the case, then post 1920s construction would very well have something other than lead service lines.

Tuur · Monday at 8:48 PM

More checking:

Beware AI here: I just looked into leaching, and an AI search result warned about lead from plastic pipe because of lead solder. You don't solder plastic pipe; you solder (sweat) copper pipe. Modern solder for that purpose doesn't use lead (maybe silver).

Note: Doing this part-time, my old boss was leery of soldering because of torches used close to wood, which is where I learned flaring and using connectors to join copper pipes. I have zero experience sweating pipes and am very careful with sweated joints lest I break them.

Anyway, another source of lead is brass made with lead as part of the alloy, and brass is common in plumbing fixtures.

Leaching is interesting. Low PH water will do it; heavy mineralized with high PH is less likely. But high levels of chlorine can cause leaching. Apparently, a scale can form in lead pipe that can slow or stop leaching, but low PH can do a number on it. Didn't find mention of it, but if you bang on old galvanized pipe you often end up with rusty water, and my guess is banging on lead pipe will do the same thing to the scale, so it might not necessarily require chemical means to remove the scale and renew leaching.

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A century of hair shows how lead exposure collapsed

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