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This feels like a good time to bring up the lead-crime hypothesis (flaws and all). For those who don't know, there's a strong (if faulty) correlation between lead levels in preschool children and crime rates: https://www.vox.com/2016/1/14/17991876/crime-drop-murder-lea...

https://en.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesis

Regardless of what you think about the hypothesis, the growth and crunch in lead levels during the last many decades is astounding and probably still has many bad effects on IQ and related factors, at least in the US

I like this roundup [1] as it hammers the point home with tons of observations across cultures, times, contexts, and methods of analysis. For instance, different cultures phased out lead gas at different times, and their subsequent crime charts were offset by the equivalent years.

[1]: https://www.motherjones.com/kevin-drum/2018/02/an-updated-le...

Thanks, this is way more thorough than the links I was able to find / select from a quick search at the time.

If anything, I think I've accidentally experienced a lesser case of [Cunningham's Law](https://meta.wikimedia.org/wiki/Cunningham%27s_Law), where the veracity of the hypothesis is arguably pretty clear-cut and I just lacked the evidence, and the internet is obliged to correct/help in that regard!

The prediction about lead and terrorism is pretty bold, but would be interesting if it were proven true:

https://www.motherjones.com/kevin-drum/2016/12/prediction-te...

I'm skeptical because of the number of factors involved in something as complex as terrorism but I give credit to the author for thinking of it and openly predicting it.

The car and its consequences has been a disaster for society. Even today we are pumping so many toxins in to the air to deliver a slower, less efficient, and more expensive form of transport. And it's not a problem that EVs or self driving cars can solve since a huge amount of the pollution comes from tires.

In lots of places the tailpipe emissions of a modern car are cleaner than the air.

CO2 is a pollutant, but it's not a toxin when the concentration is low and oxygen is available.

That conveniently ignores the non-tailpipe emissions, for example dust from tires and brake pads. I also suspect that it's only true in the lab, I have the pleasure of cycling through many clouds of noxious soot from supposedly modern cars whose owners just happen to press the throttle harder than what the NEDC requires.

I find the first statement hard to believe. Running a car in a closed space is deadly.

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"I'll take 'facile and reductive statements' for $100 please, Alex."

CO2 is demonstrably emitted as a pollutant, but it's only a fertilizer in pretty poetic sense: Plant growth is bottlenecked by other factors.

And water is essential for life, so that must mean it’s impossible to drown, right?

Funny that people who say things like this and “CO2 is only 0.04% of the air” don’t want to try injecting 0.04% of their blood volume of hydrogen cyanide and seeing if such a tiny amount of something can have an effect…

So is rape ....

https://yaleclimateconnections.org/2020/12/more-co2-in-the-a...

By that logic, so is ammonia.

Care to take a big huff off a farmer's anhydrous ammonia tank?

> Even today we are pumping so many toxins in to the air to deliver a slower, less efficient, and more expensive form of transport.

Slower than what?

Walkable cities + public transport. When I had a car it used to take me a minimum of 10 minutes to get anywhere. Cars have spaced out everything so far that over all we spend so much more time traveling. Now I live in a walkable area and almost everything I need is a few minutes away on foot, or a 20 minute train trip to the main city area.

I swear that living in NYC for nearly two decades has made me incapable of making a grocery list and shopping like pretty much everyone else in the country (only slightly kidding). I just walk down the street and grab what I need.

I did just miss the 6 train by 15 seconds and am standing on the platform as I write this, which I guess is annoying? I’ll take it over driving in traffic though.

Whenever I leave NYC and go anywhere else in the US, walking a mile feels like an act of silent rebellion.

Had a friend from Texas move near me in Australia and they have just been exhausted trying to keep up because they aren't used to walking. Walking here is the fastest and most convenient way to get around. By the time you get your car out and find parking, you could have already been there on foot.

You'll observe that the rate of obesity is extremely low in the walkable areas which I really think is heavily because the people there live more active lifestyles just getting around day to day.

The rate of obesity is low because of survivorship bias, nothing more, nothing less. For obese and/or disabled people, living in New York is an absolute nightmare if you can’t afford public transit.

Despite loving the city amenities, culture, nightlife, one of my family members had to give up and leave NYC because he couldn’t afford cabs everywhere and hated showing up to events late and sweat-soaked otherwise.

> The rate of obesity is low because of survivorship bias, nothing more, nothing less

You think the rate of obesity is not at all affected by the amount of walking?

You miss the point. People who want to walk and live that lifestyle live in New York. People that walking is painful for generally leave.

It’s like saying wearing bikinis on beaches seems to cause weight loss.

It's some of the effect, but absolutely not all. You said it's pure selection bias, no more, no less... That was your point.

I'm the same person, but the last place I lived I averaged 7k steps and now I average 4k steps. That clearly affects my level of health and weight.

> For obese and/or disabled people, living in New York is an absolute nightmare if you can’t afford public transit.

Obesity has increased in recent years as people from all walks of life exercise less and eat out more.

Even when adjusting for poverty and race, studies have shown that close access to parks and other walkable areas, combined with good public transport, reduces prevalance of obesity.

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Try vacationing a couple of weeks in a city that isn't build around cars and has good public transport, maybe you'll understand. Tokyo is nice for example. Note that there still are cars in Tokyo, nobody is banning cars.

Ah yes, the infamous "they", who are plotting to take away your cars, your guns, and your hamburgers.

I mean, yeah - They're pretty enthusiastically telling us that's what they want to do. It's not a conspiracy theory if they're actually advertising it...

Railfans in high places?

The subsequent evidence is so strong that I don't think it's appropriate to call it faulty. In the paper "Life After Lead" they study a boundary effect of children who were just above and just below treatment thresholds for blood lead levels and the outcomes in terms of crime, school success, etc are stark. Figure 4(F) particularly.

https://www.aeaweb.org/articles?id=10.1257/app.20160056

I haven’t read the paper, but I wonder how well they control for economic status. I’d expect the better off a family is the less lead they have in their life - and I’d expect economic status to actually be a cause of better education, health, incarceration, etc.

They said “we compare outcomes for children who are similar across observable characteristics but differ in eligibility for intervention due to blood lead test results.” Economic status is observable, so ide guess it’s I caused; but I only read the abstract.

Late Soviet writers such as Strugatsky brothers would often bring out the topic of barbarism and brutality which is characteristic of Human race and had to be fought at all times...

...which is, as far as we know now, not innate but looks like symptoms of chronic lead poisoning.

Lead poisoning is far from the _only_ cause of the darker side of human nature.

The surprising is that this side turned to be manageable.

People around them ended up not wanting to actively destroy themselves and their environment. That was the big surprise of 00's and it coincided with aftermatch of when the lead gas was outlawed.

It seems based on the last years' news that the USA is having a reenactment of that now, though. I wonder what it takes this time to fix things.

I think the "crime is caused by exposure to lead" hypothesis has taken a major hit in recent years. The homicide rate went from 4.99 per 100,000 in 2019 to 6.81 per 100,000 in 2021. There was no sudden increase in lead exposure, either in recent years, or decades ago, that can explain that increase.

I'm not saying that lead has no effect on crime, but some people were claiming that lead exposure was the single primary cause of violent crime. When you get sudden changes in the crime rate like that, it's pretty clear that something else is going on.

The existence of other variables obviously does nothing to eliminate the lead exposure variable.

> some people were claiming that lead exposure was the single primary cause of violent crime.

Examples?

What is a faulty correlation? They're correlated or they're not. There's may be a faulty casual attribution, but that is another topic.

I had meant that despite the statistical correlation being objective and strong, the logic behind a causal link was faulty.

That might not be the case though (?), see https://www.motherjones.com/kevin-drum/2018/02/an-updated-le... from the other reply

Do you mean faulty, logic, or faulty, supporting evidence? I think if something is plausible, but unsupported by evidence, the logic can be sound, but the supporting evidence faulty; but if something is implausible, then it would be the logic that was faulty and to me it seems like that crime and behavioral changes are caused by lead is certainly plausible, so I don’t think it’s a logical failure here. It may just be a failure of the evidence.

So.. How do you know the evidence is faulty, though? I mean, can you definitively prove it’s faulty? if you can’t, then you have to consider there’s a possibility that it’s causal?

See above. The Vox article made this seem like logic around the hypothesis is more faulty than it probably is, given other replies.

I understand my meaning might've confused HN commenters but I genuinely feel that the intent of my words in the initial comment is intuitive, and don't have time or bandwidth to argue about the semantics. I am sorry for the confusion. I obviously can't definitively prove it is faulty, and was merely trying (likely incorrectly so) to summarize the believed veracity of the hypothesis.

Vox, always shillin' for illogic. Hahah

I thought that's what you were doing, intuitively, and I wasn't attacking you. I know how it can feel that way. It's more like a jumping off point for other commenters to hop onto, a group conversation if you will, but the threaded nature does make it look like a direct challenge/reply to you.

You know you can't be sorry for other people's confusion tho, right? That might be some semantics for you! :) haha

Have a good day and thanks for sharing this interesting ref!

selection bias can cause faulty correlations. If you select on the basis of a correlation, you don't get to say you found a correlation.

I remember reading somewhere that lead exposure might correlate with poverty. Is this accounted for?

It does correlate, and it is accounted for. We have evidence to believe the causal arrow points lead=>poverty. This is because the natural experiments of phasing out leaded gasoline in different countries at effectively randomized times produce subsequent decreases in lead poisoning (and downstream crime). This is as close to a controlled "give one population lead poisoning" experiment as you can ethically run.

But there is also poverty => poor housing in less desirable areas => more pollution in general. Including Air pollution, car exhausts, lead from leaded gasoline.

This is well known e.g. (1) and seems like it would be a large effect.

I'm not saying that this invalidates the studies on lead, I'm sure that the researchers know how to do it far better than I do, and have spend a lot more time on accounting for it; just that poverty drives increased pollution exposure, as a general rule.

1) https://www.london.gov.uk/%20New%20report%20shows%20shocking...

For poverty effects to dominate across countries, there would need to be a causal relationship between phasing out leaded petrol and countries' distribution of income; it looks implausible at first glance. It's much easier to phase out leaded petrol than to make persistent changes in the distribution of income. It would be very surprising if all countries not only did so, but did so at the same time.

Quite, phasing out leaded petrol at different times is the kind of "natural experiment" that can demonstrate the effects of lead reduction not poverty reduction.

This is not the same thing as "poverty drives increased pollution exposure, as a general rule" which is still true.

Other things drive pollution exposure too, like general use of leaded petrol.

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I'd like to point out that, although it is illegal to put lead in water supply lines in the US, there is a loophole that allows it in hot water lines.

As a result, for certain fittings, most big-box hardware stores only sell the leaded variants, and label them "hot water heater supply line" or something similar.

There’s another loophole: “lead free” means that the wetted surface is no more than 0.25% lead (by mass, I think).

As far as I know, lead has nice properties as an element added to brass alloys. Which is not an excuse for using it, IMO.

(Why is any of this still a thing? Stainless steel is cheaper than copper these days, and it’s a great material as long as you aren’t trying to screw one piece of stainless steel into another, and there isn’t a great reason why one should need to do much of that. And there are some excellent plastics available, too.)

Are there? It seems like plastics are shaping up to be the modern day lead.

Lead roofing tends to get recycled into bullets in time of war, but those roofs that don't, are typically there forever (400+ years) and never leak. Some plastics are UV resistant due to additives but even copper struggles to compete with lead as a roofing material. You only need to look back to the 1970s to find PEX water piping and the disaster/flooding it can cause due to age.

Are you thinking of polybutylene pipe, rather than Pex (cross-linked polyethylene)?

> Lead roofing tends to get recycled into bullets in time of war

That's interesting - I've read that there are a lot of castles and stately houses whose demise started from the owners selling off the lead roof, but I never understood why it would be so valuable that you'd destroy the building for it. Is that why?

Quite a number of British monastic churches and castles had their roofs sold off by Henry VIII, who was fully intending to destroy the building.

Using McMaster-Carr as a benchmark, lead sheet is a bit more expensive than the same size and thickness of 316 stainless sheet. One of these is extremely toxic and the other is pretty much harmless. (Also, 316 stainless won’t magically corrode if there’s condensation on it, and the Internet suggests this is a problem with lead.)

Sure, lead can be molded into place with traditional techniques if you can find a competent roofer with a sufficiently minimal desire for self-preservation. But modern standing seam roofs work pretty well.

Hopefully you don't have a fire....See: Notre Dame

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Those don’t seem like comparables though. Lead is just one (or arguably a handful of) compounds, while there are at least dozens of species of plastic.

I highly doubt it. They don't seem to be perfect, but they clearly aren't anywhere near as toxic as lead.

Plastics for potable water tend to be copper lined where I live, not sure what is used elsewhere.

I've never heard of copper-lined PEX, can you tell me more?

I think op may be referring to 'barrier pipe', which is a plastic -copper-plastic sandwich, which is designed to keep out pollutants which can diffuse through the plastic - eg. Diesel oil.

If you don't use it for underground water pipes in cities, you'll normally get complaints from homeowners about 'chemical smelling' water, particularly first thing in the morning when water has been sitting stationary in pipes all night.

oh dear i forgot that plastics are permeable to petrochemicals lile paper is to water

There is a test for plastics where they weigh a block of plastic then soak it in water and weigh it again. For some plastics the gain in weight can be a few percent.

That's like saying "metal is strong". There are huge differences among different plastics.

Well, there are < 100 metals but thousands of varieties of plastic?

Not thousands, certainly not in common use. But yes there are many, and they have very different properties from one another, including permeability.

Barrier PEX (often referred to as PEX-Al-PEX) uses a layer of aluminum, not copper. A far more common type of barrier PEX uses a low-permeability polymer coating.

Oooooohhhh.. That make sense. Today I learned.

I still have a length of it in storage but I don't know the brand by heart. It was pretty expensive stuff and it needed weird fittings, which were also expensive, the inner liner was blue, that much I do recall. In the end I mostly regretted going for plastic, I'd probably use regular copper pipe and crimp fittings again, less hassle and I'm just more familiar with it.

Do you mean PEX-Al-PEX? It’s mostly obsolete now, in favor of “oxygen barrier” PEX. The latter is generally approved for potable use, but there’s no reason to use it. It’s intended for closed-loop heating or cooling systems that contain non-stainless iron alloys, and the idea is that any oxygen initially in the water will be rapidly depleted, and deoxygenated water is not corrosive.

Probably alupex "meerlagenbuis"? Comparing it to copper it seems to be much more affordable per meter. I worked mostly with copper in the past, but did some work with alupex on my brother's house a couple of years ago. It's much more convenient and affordable than copper!

I recently fell in love with copper pipes. So many advantages, so easy to work with. Quick and nearly fool-proof.

I tried introducing some stainless fixtures and did not have a good time with it.

I'm not a pro by any means but I do all of my own plumbing and gas work in my house. Haven't had one issue out of iron gas pipe or copper water lines. I was actually planning a pex install/replacement, and I have worked with it in my camper, but I changed my mind after doing some more work with copper recently (replaced water pressure regulator). Waaaaay cheaper than messing with pex.

People often go to Pex because it's way cheaper than copper. I use copper because the rest of my house supply is copper, soldering pipe is a skill that I have and enjoy using, there's a slight anti-microbial action from copper, and I trust it to last longer than I have years left around. I sure don't do it because it's cheaper, though.

I know some plumbers recommend Pex because it fails catastrophically -- if you run a nail through a pipe you'll know it -- whereas copper can have pinhole leaks which will slowly grow mold all over the inside of your wall without you noticing.

Straight new install of PEX might be cheaper but I can reuse copper fittings and they cost nearly nothing. Same with the runs of pipe...I can reuse copper without losing length. Just easier to deal with for maintenance.

I had a house where a brand new copper line corroded and started leaking 2 years from installation, and I don't mean at joints or anything, I mean the local water just ate right through the wall of the pipe. I switched to Pex and was fairly happy with it.

I never did do the research to figure out what was up with the water, but similarly, when I tried inventing my own sump-pump sensor by dipping copper wire into the sump well, it ate the copper wires apart in 3 days. I tried again with stainless rods and discovered that there was about .05 Volt per inch deep I put the sensor, i.e. the stainless rod near the top of the well would be about 2V higher (or lower, don't recall) than the stainless rod that ran to the bottom. Made it kind of annoying to design the circuit.

Looked in to this seriously for a product some years back. Captured ping pong ball floating on the surface of the water hitting a physical limit switch is the way to go. Otherwise ultrasound.

Convenient point for PEX: If copper pipes aren't properly grounded they'll tend to develop pinhole leaks within that timeframe.

Due to galvanic corrosion / electrolysis?

I'm not a plumber, that's what someone told me once a long time ago. But googling some more, systemic pinhole leakage can also depend on several factors like water cleanliness and pH, with some counties finding grounding doesn't cause pinholing and others finding it does.

The subject may be more complicated than my single sentence can capture.

I assume you have a well, not city water? Utilities generally try to adjust their water to be non-corrosive to copper.

If I used well water or had another non-city source, I would do my best to keep copper out of the plumbing and I would minimize brass as well. Stainless steel and plastic, please.

I assume the copper wire was designed as a simple resistive switch? That will cause electrolysis and corrosion. There's an improved design that involves measuring capacitance, which also uses less power. I have a commercial sump pump monitor that works this way.

Yep, but in the end I was able to switch by monitoring the voltage generated by the water on the stainless rods, using a microcontroller. Worked great for a few years until I moved out. Haven't had a sump pump since. (good riddance)

Stainless and copper do not mix. See galvanic corrosion.

Stainless steel is just fine in a copper system if it’s not electrically connected to the copper. Even if it is, you are unlikely to have problems unless the wetted area of the stainless steel is comparable to or larger than the copper, in which case you may accelerate corrosion of the copper.

You won’t have the problems you would have with galvanized steel. Copper ions leached out of a copper pipe will react with zinc and non-stainless steel and can very quickly degrade under some conditions even without electrical contact. Stainless steel, not so much.

(Don’t let rainwater that came from a copper gutter or that ran over treated wood hit a galvanized steel flashing. Really, just don’t use galvanized steel flashings at all.)

Stainless in (or near) contact with copper with moisture between them forms a battery, which will corrode them.

Metals in a plumbing (i.e. wet) system need to be either isolated from each other or be galvanically compatible.

This applies to roofing, too. Nail the flashing down with galvanically compatible nails, or you'll find the flashing all comes loose after a couple years.

> Stainless in (or near) contact with copper with moisture between them forms a battery, which will corrode them.

Not really?

A battery has two paired half reactions. Something gets oxidized, something gets reduced, and electrons flow through the conductive bits.

So if you have some metallic zinc, and you have some copper ions, and you have some metallic copper, and you have electrical contact, zinc will be oxidized, copper ions will be reduced and plate into the copper, and current will flow. Once the zinc is gone, if you had galvanized steel to start with, the iron will oxidize.

Now try stainless steel. The half-reaction involving the stainless steel, hmm, doesn’t involve iron — the iron is physically separated from the electrolyte by the passive layer. Chromium? Barely - a tiny bit oxidizes and then it stops. We’re left with 2H+ + 2e- -> H2. Which can happen without the stainless steel too, but with more available surface area, it’s faster.

So a lot of stainless steel will accelerate the corrosion of a small amount of copper. But the reverse has little effect.

There is apparently a real concern the with H2: some grades of stainless steel are apparently rather susceptible to hydrogen embrittlement.

I'm not a chemist, but I believe Boeing when they told me never to place copper in contact with stainless, due to galvanic corrosion. Corrosion is the mortal enemy of all airplanes.

You'll also find the same if you google for copper and stainless galvanic compatibility.

I had no idea it was unsafe to drink from green garden hoses until it was pointed out by an RV salesman trying to sell me a white hose for potable water-- in my 20s. I thought he was full of shit, but I was proven wrong.

Hot water lines can't be the only loophole causing lead ingestion.

Interesting, I had no idea (I thought only the fittings would have lead, but it's the hose material):

https://toxicfreefuture.org/press-room/new-study-rates-best-...

Dear mother no why? Why does the Home Depot garden hoose have 6.8% led in it ...

All these small environmental dangers add up. And they are so hard to keep track of. I would never suspect a water hoose to contain led. Let alone 6.8%.

Yep. The best part is: I loved drinking from green hoses as a kid (maybe it explains a lot about me now). Even when the hose was left in the sun, the water always tasted like a cool mountain spring...because lead has a sweet taste to it. I assume this also explains why small children eat leaded paint chips, and dogs love puddles of [unleaded] antifreeze runoff (they say they changed the formula, but it looks and smells inviting to me).

The dangers really are hard to keep track of. It's too easy to blame the consumer (didn't you read the packaging for your new garden hose?). Now the threat is plastics, which requires a materials science degree to understand as a consumer.

For decades, lead compounds have been used as processing stabilizers in PVC, which has spread the shit everywhere. Hoses, electrical cords, and vinyl window blinds have historically been big sources.

Things started changing in the 2000's when companies started seeking compliance with E.U REACH and RoHS regulations. Garden hoses are now largely lead free, as are blinds, but electrical cords have taken longer to switch over.

Damnit. I thought the Proposition 65 warnings on Christmas lights and Ethernet cables were just crying wolf.

> I thought only the fittings would have lead, but it's the hose material

It can be either, depending on context. (Being pedantic here just so nobody comes away thinking it can only be one or the other.)

The guy who pointed it out to me was making a sales pitch for an RV, so the hose he was upselling was for potable water-- the fitting for it on the RV was presumably selected for potability as well. Connecting a white hose to the spigot on your house could mean you're passing dirty water through a safe hose.

To be real anal, with aquaculture you have to screen fittings for other metals too. Exposure to brass will kill pretty much everything in a saltwater tank.

When I moved I did a search not only for garden hose without lead but also without phthalates and BPA. There are a few goodun’s out there. Expensive though, but I also have hose connections that don’t leak because tolerances and decent seals.

In particular I would recommend the ELEY Garden Hose

Eley makes really good (but expensive) stuff. It bugs me that they moved their production overseas though. I could understand if they were selling a $5 sprayer or $15 hose reel. I think they could still make a good profit if their stuff was made back in Nebraska.

Water Right is about a third of the cost. I've left mine out in the sun for three years for one hose, four for the other. The 4 yo one is just started to get a hint of bleaching this year.

Good luck with Water Wright. They come in long runs and aren't very heavy. Occasional problems with inventory, but do you really need the red one?

Hose water is delicious

Why are there so many loopholes in every single US law?

Everytime there’s a major health issue or anything extremely anti consumer it’s because of a loophole in the formulation of a US law.

Are US lawmakers that bad? Or is it judges who interpret laws literally instead of using the intent?

It's much easier and faster to pass a law with loopholes that still removes 90%+ of the bad stuff you want to remove.

If you try to solve 100% of the problem you have the bad stuff on the market for another 10 years while the details are sorted out.

Or you just ignore the details and ram through the bill, and find out about a lot of unintended consequences and have a mess.

Ideally, politicians would pass the bill with loopholes first, and then follow up and try to close them to finish solving the problem. But that's one of those things like refactoring and code cleanup that you always mean to do and never get around to.

It’s money. The answer is money. Somebody makes money by producing lead-infused products, so they pay off lawmakers to add a loophole that allows them to continue making money.

Yet people still maintain the popular fiction that corruption isn't that common in the large western countries, and that it's somehow more prevalent in the east. It's nonsense.

Everywhere there are large governments, there is huge corruption that is literally killing people so that others may be enriched without working as much.

Corruption exists everywhere, but in western countries is a lot less likely that you'll be bribing police, school teachers, medical services, banks etc as an 'individual' to get the services you expect from them. Can you find examples of people bribing those in those positions? Sure, it can and does happen. And on the whole, it's the exception rather than the rule. And definitely not at the scale of other countries.

Big business interests affecting policy for the point of profit is a universal issue though.

A small government wouldn’t magically solve this problem though

>A small government wouldn’t magically solve this problem though

You'd have a lot fewer corrupt officials though.

Well there are so many social issues that suck the oxygen out

Bill Gurley’s recent talk is worth a watch https://youtu.be/F9cO3-MLHOM

That's an excellent talk. Thanks for posting.

Why can antelope still run faster than most cheetahs?

What I mean is that you only see what survives. The thousands of products which used to have lead which don't anymore are gone, out of sight out of mind. The ones which someone forgot, or someone bribed a politician to preserve, or even ones which were created specifically afterwards and which the law had no way to even know about, to ban, are what you see.

Dynamic systems have this property, and it's hard to get permanent dominance since both sides keep adjusting.

People shit on California's Proposition 65, but the notices at Fry's made me aware of the lead content of solder, and the ones at Michael's highlighted the lead in Christmas decorations, lights, and fake trees/garland.

I went most of my life ignorant of all of this. But banning stuff outright seems like it would be counterproductive to either industry (banning soldering would be disruptive) or public image ("Liberals declare war on Christmas!").

(Tangential mention of McDonald's, whose warnings highlighted the acrylamide released in the potato-frying process.)

Lead-free solder exists though. It works fine - particularly for plumbing where you don't have tin-whisker concerns.

The only problem I've ever had with it is (1) that it turns out Bunnings in Australia sells utterly atrocious flux (the good stuff is also non-toxic, potable compatible and made in USA - and it works perfectly) and (2) that people aren't aware enough of the problem (i.e. my parents house has lead solder all through the plumbing where my father didn't know there was a difference and extended it).

EDIT: For any Australians out there - this one - https://www.totaltools.com.au/154135-la-co-56g-soldering-flu... - buy this one. This is the one which works.

Artist here. The UK had/has a ban on all lead white paint. Real bummer. Ti white works in a pinch, but it has dramatically different properties.

If you write laws without an exceptions for exceptional cases, then you get more laws with unintended consequences.

> Or is it judges who interpret laws literally instead of using the intent?

It's hard to interpret intent in a way that is consistent and fair. A ruling that does not go by what is written down is open to be criticized, while a ruling that adheres to the letter is almost never overturned.

Us lawmakers are effectively the employees of the people profiting from skirting these health issues.

> Why are there so many loopholes in every single US law

Bribery of politicians

There are often fairly sensible reasons or good intent behind many of them. People don't normally drink hot water; it's not a great idea, as it has higher levels of dissolved solids and higher risk of contamination by organisms (like legionnaires). Meanwhile, lead helps make metals and solders more resilient to high temperatures and fatigue at low cost. Banning lead from the hot side could therefore decrease reliability and increase cost, for arguably little to no health benefit.

I don't have a vested interest in the lead industry, but it's pretty clearly not simple maleficence.

Basically nothing you said here is true.

People don't normally drink hot water

People drink hot water all the time not to mention cooking, tea, instant coffee and more.

legionnaires

That's from water being stagnant for long periods of time.

lead helps make metals and solders more resilient to high temperatures

Not only is this not true, but water is never going to go above boiling. Propane torches (used for soldering pipes) burns at 1,980C

Banning lead from the hot side could therefore decrease reliability

This is ridiculous. Soldered pipes have been in use for over 70 years. Where are getting this idea?

> People drink hot water all the time not to mention cooking, tea, instant coffee and more.

I always use cold water and then boil it in a kettle. Even in Europe with our copper pipes the heat will dissolve more crap apparently. It's always advised to do this.

> That's from water being stagnant for long periods of time.

Yeah stagnant under optimal bacterial growth temperatures like 30C. And it enters the body through the lungs, from vapors in the shower. Not drinking it doesn't prevent legionnaire disease.

In fact what does prevent it is heating the water significantly, like around 60C. And chlorinating. It's also why the water here in Spain it's almost undrinkable from all the chlorine here in summer. They just have to put that much in it to prevent outdoor pipes growing bacteria. Yet in summer the water is still hot and brown when I open the tap after it's been outside in the pipe all day. I drink a lot of bottled water, lol.

> Not only is this not true, but water is never going to go above boiling. Propane torches (used for soldering pipes) burns at 1,980C

Yeah lead solder actually melts at a much lower temperature. I still use it for that reason because lead free is a bitch to work with. I only solder micro electronics though.

I always use cold water and then boil it in a kettle.

That's great for you. This has nothing to do with how absurd the idea of using lead in 'hot pipes' would be.

Not drinking it doesn't prevent legionnaire disease.

I didn't say anything about drinking, I just said it comes from stagnant water.

I still use it for that reason because lead free is a bitch to work with. I only solder micro electronics though.

Lead free solder is very easy to work with when putting copper pipes together. The torch puts out a lot of heat and you don't have to worry about destroying anything near it (except for wood behind it). I can't imagine all the twisted logic it would take for someone to think using leaded solder in pipes is a good idea.

One time I sweated a joint about 1 foot away from an electrical line running inside a steel conduit. The ambient heat (plus, I guess, whatever load was on the wires) was enough to melt the jacketing and cause a short.

I wash my cups and dishes with hot water, then I drink and eat from them later.

> legionnaires

Actually, this is famously caused by having water that’s not hot enough. It became a problem in some countries when they advised lowering boiler temps to save energy.

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I had a stop valve that went bad and I wanted to replace it with a ball-valve because I prefer quarter-turn valves for shutoff valves. No ball-valves at the hardware store were lead free.

just a fair warning that you should close that quarter-turn valve very gradually when there is running water if you ever find a non-leaded version... water hammer can and will burst the weakest of your pipes.

If we're warning about valves, be sure that your gate valves are fully open (or fully closed), otherwise the gate will erode and may erode to the point where it can no longer close.

For those that do not know, Practical Engineering has video on it: https://www.youtube.com/watch?v=xoLmVFAFjn4

Less of an issue for area shutoff valves (e.g. under-sink) , since most of the time they are used before doing maintenance and there is little flow at the time.

We did have a plumber (!!) damage our pressure regulator by turning the whole-house shutoff valve (inches away from the regulator) too quickly; that was a bit annoying.

It would be extremely difficult to cause water hammer with a ball valve. They're just too difficult to close quickly.

Water hammer is a huge issue with faucets, which can be closed quickly, and with electrically actuated valves such as in washing machines, which close very quickly.

Is this actually a thing? I know there are videos of watwr hammer on youtube (US centric)

There are no regulations afaik in Europe in domestic = no-industrial plumbing and sure we have quarter valves which you can quickly turn off. I never ever heard of a bursting pipe because of water hammmer.

I am a plumber and sprinkler tech (nyc) and literally have never seen a broken pipe that could reliably be traced to water hammer damage.

Really would only be concerned if you are building fire safety systems. Now those sudden GPMs need some support.

I had a problem just this past summer hooking up a pressure washer to a hose outlet. After two hours of constant on-off cycling, had the pipe leading to the hose bib burst. You could hear the water hammer quite clearly (and violently!) after I repaired it, so I went back and added a hammer arrestor.

To me what I hear: your pipes weren't supported and your pressure is too high if it can be described as violent. I can hear my old office's script telling me to sell you a PRV or two.

I hear what you’re saying but isn’t it a bit of six of one and half a dozen of the other? The high(er) pressure relative to what the pipes could withstand exacerbates the effects of water hammer induced by the pressure washer’s solenoid constantly slamming open and shut in the matter of milliseconds, no? Lower pressure (via a PRV or otherwise), higher-rated pipes, slowly opening and closing valves, or strategically installed hammer arresters are all (theoretically and to various extents) viable solutions, no?

Because you are fixing symptoms (w/ another failure point) with local solutions and not the disease (high pressure, bad or unsupported pipes) and good plumbers do not do that because A) ethics B) liability

If your question is can those gas piston water hammer arrestors protect fixtures-- sure, I mean that part is just physics. Whether it's worth it before a hosecock is a completely different matter -- also as per the OP you're far more likely to break a toilet valve just from handling than from water hammer.

I use quarter turn ball valves everywhere and slam the crap out of them. If a pipe bursts from that, it needs to be fixed, and I’d rather it happen while I’m there slamming valves around than when I’m not home.

But it has never happened.

Ah yes, the chaos monkey approach to plumbing. I buy it. The best time to have a leak is during or immediately after doing plumbing work. The worst time is when you are asleep, out of the house, or on vacation.

Isn't it code nowadays to have water hammer arrestors that trap air and create a cushion?

Plastic piping (if equipped) functions as a water hammer arrestor. An expansion tank will as well, though a picky inspector may insist that the automatic valve location must have a water hammer arrestor if you are piped with metal supplies.

I know expansion tanks are required by IRC these days and those can help with hammer a bit too, as they're doing a similar function.

It happened to me once, now I turn off the water when I go on vacation.

you don't have embedded copper water lines in concrete slabs I assume? sure a little drywall damage is nothing but having to jackhammer that up is a bigger ask.

I've seen people just abandon those lines in favor of running pex through the walls rather than fix them.

When I lived in South Africa and the power went off frequently, the water went off because it couldn't be pumped. It absolutely was a thing in the water came back on. I could totally hear it in the roof.

And/or stick a hammer preventer in your piping in multiple places.

A timer sprinkler system kept water hammering, and I bought a little device that completely stopped it.

If you're in the U.S., Home Depot sells Giancomini ball valves (branded "Everbilt") that are lead free. They're rated for water and gas.

If you're looking for stops for faucet and toilet supply risers, then they're pretty much all lead free now. SharkBite and BrassCraft, for example, only make lead-free stops.

Something interesting to point out is that until about 2014 "lead-free" plumbing could in fact contain amounts of lead. I forget the cut-off level but it was something like 8%.

I'm not all that worried about lead. In most places it's not an issue because of how restricted it's been, we have tests for it in products, tests in people, etc. I'm more concerned about plastics, forever chemicals, etc which are everywhere, aren't routinely tested for, and have known negative impacts (not on the same severity as lead).

This comment doesn't make sense, particularly wrt TFA.

What doesn't make sense?

the article says it's more poisonous and causes more IQ loss than previously thought.

Yeah, and I still don't find it that concerning given the low prevalence and still relatively low IQ per ug/dL reduction. Slightly lower IQ is more appealing to me than things like cancer.

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So most likely that is focused on hydronic heating systems. Personally at my local home improvement store all the fitting in the plumbing section are listed as potable/lead free.

If you have some examples of fittings that you are referring to I would be interested. I can only really find hydronic circulator pumps that are only low lead instead of lead free.

A few feet of hot water pipes in fittings won't create a problem. Think of the thousands of feet of pipe that water runs through, where it often sits for days, then spends a fraction of a second in a tap or shower nozzle. Worried? Just run the tap for half a second before drinking.

That depends on the chemical makeup of the water (I think PH, but maybe something else). Some water will dissolve lead quickly and thus be unsafe, while others will not. Some water will leave a coating on the insides of pipes and so the lead doesn't even touch the water (this coating can build up over time though), while others will clean that coating off and so lead can touch the pipe.

That doesn't make any sense. Half a second is barely enough time for water to move through the hose from the wall to the faucet.

What are we going to do? Pass a law? To force the millions of voters paying hardly any property tax who bought their lead-loaded homes in 1983 for $40,000 in Los Angeles and San Francisco, now worth $1.1m, to you know, fix them? Then will we pay for the even greater rise in rents? I hate lead, pollution and my incredibly cheap landlord, but I feel like I have no choice in California.

That seems like a non-sequitur. He's saying that new fittings contain lead. Step one is to ban those.

This does leave existing homes with old fittings, but "stopping the bleeding" doesn't require retrofits. The old housing stock will gradually be replaced/updated. Accelerating that trend is the logical next step, but it's a second, separate step.

> What are we going to do? Pass a law?

Yes!

It wouldn't burden existing homeowners because such laws almost always grandfather in existing structures.

When they banned lead paint and asbestos, I don't think anyone immediately repainted their walls or replaced their asbestos drywall. It slowly phases out over a number of decades.

> When they banned lead paint and asbestos, I don't think anyone immediately repainted their walls or replaced their asbestos drywall. It slowly phases out over a number of decades.

Kinda. Or, rich people got it replaced right away. Poor people are still living it with it today.

Go test a $500k and a $100k (this is midwest price not SF price) house for Lead and Asbestos. I bet you find very different results on the average.

My grandmother's house still has asbestos in it ($400k house in New York). Short of tearing her house down and building a new one there's no way to fix that, but decades later I'm benefitting from the ban by living in an asbestos-free house built after the ban. Gotta start somewhere even if the benefit isn't felt by everyone at the same exact point in time. It would definitely benefit the rich first since they tend to be the ones building new property.

There's zero harm from asbestos as long as you don't mess with it. Your grandmother is safe.

Tearing her house down, on the other hand, can actually be bad for her, if she's staying near it while they mess with her asbestos.

There's not really any issue with asbestos as long as you leave it alone and don't mess with it. It doesn't need to be torn out unless you're renovating.

> "THE BEST THING TO DO WITH ASBESTOS MATERIAL IN GOOD CONDITION IS TO LEAVE IT ALONE!" [1]

[1] https://www.cpsc.gov/safety-education/safety-guides/home/asb...

Kinda hard to do when your ceiling is covered in delicate popcorn asbestos that showers down on you every time it gets touched. This is very common.

If they're crumbling or damaged they should be abated, but if they're in good condition they don't pose a risk.

There is no such thing as a popcorn ceiling that doesn't crumble every time you so much as change a lighting fixture.

Inequality isn't an argument against taking the necessary regulatory measures, it's an argument to work on the inequality (or subsidize the retrofits).

"It wouldn't burden existing homeowners because such laws almost always grandfather in existing structures."

In Mass you have to de-lead for any tenant with children under 7 or so, and it's illegal to discriminate by choosing tenants without children. No grandfathering.

You obviously didn't live in the SF Bay area in the 80's. Houses were not that cheap even then.

And they're more than $1.1m now.

Use a water filter.

There is also an exception for leaded gas in small/private jets ("AVGas") so its used in some of those formulations.

No jets use or have ever used leaded products. Jets run on Jet-A, which is a close relative of kerosene. It has never been leaded. The purpose of lead was to prevent cylinders from prematurely detonating ("knocking") in internal combustion engines. Jets do not have any cylinders to knock; the fuel burns continually in an open combustion chamber.

You may have been thinking of 100LL (100 Low Lead) fuel for piston engined planes. Many airports stopped selling 100LL in January of 2022. The FAA has approved a lead-free replacement in fuels like UL94 that are steadily replacing 100LL.

At last! I live in France and it is still 100LL everywhere, except for ultralights which mostly use automotive gas (mogas) or sometimes UL91.

But do they actually sell it everywhere? My experience with aviation is that change happens incredibly slowly. The simple fact that they still use that abomination that is 100LL is telling. Poisoning thousands of people for decades just because of paperwork essentially. As an amateur pilot, I understand the idea of using only tried and tested solutions, you really want things to be reliable up there, but our representatives can at least make the necessary efforts to make our already environmentally questionable hobby not needlessly poison people.

> Many airports stopped selling 100LL in January of 2022.

Really? That is news to me. Googling reveals that two airports did that, both in the same county: Reid-Hillview Airport (KRHV) and San Martin Airport (E16).

Bay Area bias, sorry. Many airports near me did. I have no knowledge about Oklahoma.

> Many airports near me did.

Could you list a few of the many? I looked around Bay Area airports, and found most of them selling 100LL:

  KSFO - San Francisco International Airport - $9.90         
  KHAF - Half Moon Bay Airport - $6.42                       
  KOAK - Metro Oakland International Airport - $8.21/$8.64   
  KHWD - Hayward Executive Airport - $7.99/$7.55             
  KPAO - Palo Alto Airport - $6.35/$6.95/$6.59               
  CA35 - San Rafael Airport - $6.84                             
  KSJC - Norman Y Mineta San Jose International Airport - $10.07/$8.95  
  KLVK - Livermore Municipal Airport - $6.54/$7.54                
  KCCR - Buchanan Field Airport - $7.15/$6.98                   
  KDVO - Gnoss Field Airport - $7.67/$7.87                         
  KAPC - Napa County Airport - $9.20                                
   0Q3 - Sonoma Valley Airport - $8.00                              
   C83 - Byron Airport - $6.35                                  
   0Q9 - Sonoma Skypark Airport - $6.30                  
   O69 - Petaluma Municipal Airport - $6.95

> Many airports stopped selling 100LL in January of 2022.

Judging by the size of the GA fleet, and by the fact that a sizeable portion of that fleet is not certified to fly with UL94, allow me to doubt the seriousness of that news..

It took ages, but that is finally being phased out

> On February 23, 2022, the FAA joined aviation and petroleum industry stakeholders to announce a comprehensive public-private partnership to transition to lead-free aviation fuels for piston-engine aircraft by the end of 2030.

https://www.faa.gov/about/initiatives/avgas

> exception for leaded gas in small/private jets

Jets run on jet fuel (which is basically kerosene and has no lead). Avgas is used in many piston-powered small aircraft.

That can't be the only exception. Maybe nobody sells it premixed anymore but back in the 90s we had to mix lead additive into gasoline for vintage motorcycles.

Modern octane boosters for classic cars and bikes use other types of cylinder head lubricants.

Why is it specially allowed in hot water lines?

It's not allowed in any water lines used for drinking or cooking. I would read that as not allowed on hot water lines serving the kitchen for sure (and I suspect most plumbers would agree).

The warning on items from my plumbing supply house for lead containing items is prominent, pops up on each "add to cart", and says "This product does not comply with the “Safe Drinking Water Act,” which requires that products meet low-lead standards in order to be used in systems providing water for human consumption (drinking or cooking). This item is for non-potable (non-human consumption) water applications only."

It is allowed in hydronic heating, HVAC/R, and irrigation fittings (which of course don't have a human consumption element to them).

I think that is allowed because we don’t drink from the hot water tap.

If the water was already hot because I was doing something else, I'll make soup or pasta with a pot of hot water. If the kitchen were closer to my water heater, I'd do it more consistently.

You're never supposed to cook with hot tap water. Even if lead is not a concern, there are other possible contaminants that can leech from plastic and copper pipes, or from the tank itself.

This is not taught in the US and we blend hot and cold together. Why are the lines blended at the faucet if that’s the case?

There's a lot that's not formally taught in the US. But I'm in the US and this is a thing. The blended faucets are fine. If it was set to hot or some blend with hot in it, you set it to cold and let it run for 1-3 seconds.

No, it’s blended because hot water is fine in the US. We don’t use hot water tanks that sit on rooftops and accumulate bird shit.

If you ever find yourself cleaning the inside of a hot water heater some day, it will disabuse you of that habit.

I'm sure it's mostly harmless, but they accumulate a truly horrific amount of mineral deposits and other weird gunk in there.

They accumulate gunk that was present in the cold water supply.

If its not quite hot enough you can end up having a nice incubator for bacteria

Yes, but water coming from the cold water tap has spent less time sitting in that accumulated stuff.

Seems like the presence of the accumulated gunk in the cylinder means the hot water must be cleaner by definition? The accumulation being the net difference between what was dissolved in the incoming water and what is dissolved in the outgoing water.

With the exception of gunk that is from the lining of the cylinder itself of course.

There can't be more minerals coming out than what went in though. It's not like calcium grows. Maybe it might break off and come out as some concentrated chunks, but overall there would have to be less coming out for it to accumulate in the tank.

Yeah, so the gunk has less time to fall out of the cold water.

Looking inside a kettle in London provides the same experience (at least when I lived there).

Now we live on rain water and the inside of the kettle is pristine, despite bird crap on our roof and flora in the guttering.

That's why modern kettles can be cleaned. I clean the mineral deposits out of mine once a year or so.

For things like an instapot where you add a cup of water to it, you are actually supposed to use distilled water. I used tap for years with mine and got all sorts of mineralization. It took quite a bit of vinegar to get that off, and now everything looks pristine since I have been using distilled water. You might consider using it for your next kettle, although perhaps the minerals in tap do something to the taste of the tea.

Do you buy hundreds of liters of distilled water? That doesnt sound practical

If I'm making tea I do. I can't imagine that lead is boiling off...

You should switch to using the cold water tap to fill your kettle! Also, when you see what kind of build up can happen in a hot water heater, you'll definitely want to avoid drinking from the hot water tap.

https://www.youtube.com/watch?v=kAzKts6Wp1Q&t=207s

That's not lead, that's limescale[1]. Dissolved limestone is carried through the pipes, and settles out as scale.

[1] https://en.wikipedia.org/wiki/Limescale

Yes, I didn't say it was lead. It is just a dirty, unpleasant container. Not where you want to get your drinking water, especially for tea.

It isn't just limescale in your hot water heater, it is whatever your water pipe carries in and accumulates in the tank. We lived at the beach and had to flush sand out every couple years.

Your cold water carries the same junk into your tea. It’s just missing the settling tank that would separate it out.

It is potentially a decade of accumulated junk in the hot water heater. If you aren't able to taste the difference, the data backs up the issue with drinking hot water.

https://www.nytimes.com/2008/01/29/health/29real.html

https://blogs.edf.org/health/2018/02/26/lead-hot-water-issue...

https://www.denverwater.org/tap/psa-dont-drink-or-cook-with-...

Make up your mind, does it come in or go out of the hot water tank?

It can’t both accumulate and leave at the same time.

False assumption it needs to accumulate and leave at the same time.

That's a terrible way to make tea, fwiw.

I want to stress that I actually don't give a shit (I am not that into tea, I just drink it sometimes, it's not a big deal to me), but I am curious as to why.

Unrelated to the tea, but cold water is somewhat safer to drink than water coming from your boiler, that's why.

IDK, they said "a terrible way to make tea", I'm assuming there's some sorta tea lore that I'm unaware of

There are tea drinkers that believe very strongly in using water that isn't "stale" (eg, leftover in the kettle from the last time). Presumably water from the hot water tap would be stale for similar reasons.

I think the theory is that "stale" water lacks sufficient oxygen for tea brewing to fully brew or something.

It's not O2: if you let water sit out, various things (including CO2) dissolve in it, making it slightly acidic and taste stale.

I'm not a big tea drinker, but I am definitely not a super fan of water that's been sitting out a day. There's not been time for stuff to grow in it yet, but it still tastes gross.

That makes sense.

Fill a cup with cool water and take a sip before you go to sleep. Tastes great, right? Taste it eight hours later when you get up in the morning. It takes on an acrid taste.

It's not hot enough. Black tea is usually brewed with boiling hot water around 95 - 100 °C. Green tea is usually brewed a bit lower than that at around 80 °C. But the domestic hot water supply is typically around 50 °C, to prevent burns. It'll be very weak, and probably taste a bit off. Same with coffee, or anything else that requires boiling hot water.

I don't drink tea made from hot water. I put hot water into a pot and heat it up further.

Restaurants are sometimes equipped with hot water lines from the water district and a filler tap right above or near the stove so that boiling water doesn't take so long.

I know people who fill their water boiler with hot tap water ...

Me too and it always felt wrong to me and never did it myself. Now I have a solid reason.

Oh and you should not drink directly from the warm tab water, as warm water that was standing some time, has way more microorganisms .. a point my 2 year old is not yet accepting.

I fill my water distiller with hot tap water. Guaranteed to be safe. Yes, I'm talking about a machine that boils the water, collects the steam, and condenses it back to water. It removes absolutely everything.

You shouldn't drink distilled water for a prolonged time as it will desalinate your body and depreve it from rare minerals.

A banana probably has more than enough electrolytes to counter this

The hot tap water likely has more dissolved solids in it. Over time that will precipitate into your distiller.

You can remove that by running a few cycles with vinegar. But if you fill with cold water, you'll get fewer deposits and have to clean less often.

Absolutely everything… that has a boiling point higher than water’s. It won’t do anything to remove alcohol, for instance. Or any other contamination that boils off before water does.

Ofc you could discard the head and tail of your distillation operation…

Yes, you're right in a pedantic way =). I trust that my city's tap water doesn't have alcohol in it. After all, I previously and many people still drink it without extra filtering, and it's safe enough to do so.

Relatedly, the standard technique in alcohol distillation is to discard the head because it contains toxic methanol. https://youtu.be/a1IruS1bKN8?t=672

But alcohol isn't the only thing that has a boiling point lower than water.

But when I googled hot water tap the first images it showed were... uh...

https://www.sinks-taps.com/articles/2018/9/21/the-benefits-o...

hahaha ok, but that product is a hot-water heater built into your kitchen tap to do away with your hot water kettle. Presumably, that's not plumbed to your teapot with a lead boiler and faucet. (weird, "plumbed" means "leaded")

...We don't...? Who?

In the past it was common knowledge not to. It's of much more uncertainty as house plumbing has changed.

That's because it is primarily a historical artifact[0]. Most modern plumbing heats water on-demand, which pretty much entirely avoids the risk of storage tank contamination or Legionella.

[0]: https://www.youtube.com/watch?v=HfHgUu_8KgA

>Most modern plumbing heats water on-demand

Where is this the case? These kind of things are extremely locational and here in the US it seems like 45 gallon hot water tanks are still the norm. We had a fad with "on demand" hot water heating but everyone gave up on it when the "it saves you money" part didn't work so well.

Here in Europe the money saving works really well. The issue is that you need a lot of power to heat on demand. Meaning natural gas. Having an electrical connection strong enough to heat water for a shower is rare.

I wouldn’t consider on-demand heaters to be all that modern. Places that use on-demand water heaters are now at a disadvantage because it is much more challenging to switch away from fossil fuels over to electric. Tanks, especially with a heat pump, can provide all the heating a household needs through a standard 120V15A socket. For on demand electric water heating you’re looking at upgrading main panels to supply an additional 240V20A and even that will struggle to heat the water enough in some winter climates.

Storage tanks are extremely common in Australia, but they are run hot enough to kill anything and then get mixed with cold water to bring it back to the desired temp.

Hot water heating is where it is allowed. Some houses have hot water heating which should never touch tap water and so lead won't be a problem (well it might be to plumbers working on it).

Lead is an amazing material, too bad it is toxic, because from a materials stand point it is very useful to put a little into many different metals to useful properties.

What parts of a hot water supply line contain lead. Can you share a link?

While a lot of this appears to be estimates... it's pretty wild of 30% of deaths from cardiovascular are caused by lead.

Mostly in low/middle income countries.

> It's items in the kitchen that are poisoning them

On a positive note: This is something that can be fixed.

One problem with a lot of the studies is that the studies have a lot of confoundeing and estimates of lead's harm seem to be rising even as exposure decreases, which should make people stop and think more. But this doesn't come up that much because it is obviously bad for you, and there's generally no good reason not to avoid exposure and not many people care about precisely how bad it is for you.

But it's weird that lead exposure has been dropping while the things it's supposed to cause don't seem to be decreasing in proportion to the lack of exposure.

Marginal negative impacts of lead diminish with increasing exposure, so studies showing higher sensitivities today are expected.

The idea that the effects should grow is hard to make sense of, because what's grown is only the lead exposure gap between classes, not the IQ gap. So no change in IQ gap with a change in the lead gap means the lead effect is picking up on confounding, not becoming larger.

It would have to do that be consistent with this claim that the sensitivities have gone up, unless both groups have trended down in lead levels non-linearly.

> estimates of lead's harm seem to be rising even as exposure decreases, which should make people stop and think more

Is the effect size or confidence rising? The latter makes sense. We're moving from a population systematically exposed to lead (no control) to one with lead-free kids for a change.

Effect size, at least for harm to IQ:

What is the effect of 1 μg of lead on IQ?

Good studies from the different research eras can be used to illustrate how lead effect sizes have changed over time.

Landrigan et al. (1975) represents the Early Era. In this study, there were 46 children in the high lead group and 78 in the control group. Their respective BLLs were 48.3 and 26.9 in 1972 and 40.5 and 26.5 in 1973, and they were 8.3 and 9.3 years old, respectively. So we have a gigantic 14 μg/dL gap between these groups. The high lead group had an average IQ of 88.02 versus 92.88 for the low lead group, or a 4.86 point IQ gap, and thus a per μg effect of 0.35 IQ points.

Baghurst et al. (1992) represents the Middle Era. In this study, there were 494 children who had IQ results, and they were divided into quartiles by BLLs. The mean concentrations of blood at assessment age were 6.6 μg/dL for the lowest quartile, 10.1 for the second, 13.7 for the third, and 20.0 for the final one. Their IQs were 109.6, 107.7, 102.7, and 98.7, respectively. Going from the lowest to the highest lead exposure quartiles, we have a BLL difference of 13.4 μg/dL and an IQ difference of 10.9 points. Going quartile to quartile, the effect of 1 μg of lead was 0.54 IQ points, 1.39 IQ points, and then 0.63 IQ points, with the aggregate (1 - 4) being 0.81 IQ points.

Kim, Yu & Lee (2010) represents the the Modern Era. In this study, there were 302 children who were median-split by BLLs. The high BLL group had a mean BLL of 3.74 and the low BLL group had a mean of 1.92 with IQs of 106.4 and 110, respectively. These differences of 1.82 μg/dL and 3.60 IQ points mean that the per μg/dL IQ drop was 1.98 points.

The figure in the article shows a diminishing marginal effect of increasing lead exposure, so this is all quite consistent with the theory.

I sure am wondering how much of the late 20th century Flynn effect was due to diminishing lead poisoning.

I sure am wondering how much of the late 20th century Flynn effect was due to diminishing lead poisoning

Given that the Flynn effect seemed to be strongest in the era of high-lead petrol and has dropped off, I can't see how it could have had an effect

You think the effect of a toxin is a certain curve. A giant initiative to remove it is moderately successful, but the numbers in the population are not coming down as much as you expected.

Is it that the toxin is correlated with another substance that is responsible for part of the harm? Is it corruption and the cleanups have been faked, leading to underreporting of exposure without underreporting of results? Or did you underestimate the harm at lower exposures (maybe because you underestimated the exposure of some of your subjects)?

Science is hard. As is public policy.

Sheesh I can't believe I missed one:

Corruption caused the original numbers to be incorrect, leading to anchoring in subsequent experiments.

It'd be hard for all the studies to measure wrong levels of lead in people's blood, though. How does one get all the different people studying the subject to conspire?

I'd be interested to know how someone can be sure that the cookware/tableware/cutlery in their home is safe.

Is this a result of far lower standards in other places or just a result of that being the region that was tested for the report (the post doesn't say, it just mentions that samples were collected from developing countries).

This could very easily be a massive problem in the developed world too and you wouldn't know from the report here.

Here's a study showing various levels of lead leaching into drinks from ceramic mugs found in the US:

https://foodsafetyandrisk.biomedcentral.com/articles/10.1186...

Important quote: "The estimated daily dose of lead exceeded the California Maximum Allowable Dose Level of 0.5 μg per day for one of the five mugs tested."

Previous HN discussion:

https://news.ycombinator.com/item?id=29606600

I probably dodged this ceramic problem because I drink from borosilicate glass beakers. (Yes, I buy new, unused labware for cooking/drinking use.)

Are those not too fragile for daily use? A pint glass is so much thicker in comparison than a beaker.

Mechanically more fragile than soda glass, but tougher to temperature shock -- admittedly not that useful for drinking, considering regular mugs also don't often break with boiling water. Good for cooking though: just check out the people mourning these real borosilicate Pyrex measuring cups.

To me it's mostly about the aesthetics. I've broken one or two over five years, but they are just too charming to give up on… Light, holds plenty of liquid, and good for pouring from.

I'm an adult so it's fine. And it's like $10 if I break one, no big deal.

Oh yeah, the beaker doubles as my metric-only measuring cup for cooking. It only has millilitre markings, no fluid ounce or cups at all.

They use them daily in labs, why not at home. My home is closer to a lab than a pub. No drunk people or children allowed.

I'm reminded of an old SSC post[0]:

> See, my terrible lecture on ADHD suggested several reasons for the increasing prevalence of the disease. Of these I remember two: the spiritual desert of modern adolescence, and insufficient iron in the diet. And I remember thinking "Man, I hope it’s the iron one, because that seems a lot easier to fix."

The discovery that we can dramatically reduce mortality by the relatively straightforward solution of using pots and pans that don't contain lead is a cause for excitement. Compare that to the solutions like "convince people to exercise more and eat less (or less tasty) food". We know how to make our dishes lead-free!

[0] https://slatestarcodex.com/2014/09/10/society-is-fixed-biolo...

Wow. How does one develop an iron deficiency in America? Bread and breakfast cereals are fortified with it and it's in multivitamins, eggs, pasta, most meats, and even some chocolate. I get spinach and peas aren't for everyone, but how does one end up with a deficiency in iron when it's added to the trashiest of food?

(We shit on it now, but maybe this is why the "food pyramid" was shaped so contrary to current sensibilities? Or maybe it's a potassium deficiency mislabeled as something else.)

Women literally lose iron every few weeks, and many plants contain anti nutrients (phytic acid) that bind to metals, reducing their absorption, such as beans.

In general though, I wouldn't place the blame on plants, but on the low quality, highly processed diet the average person consumes.

I have ADHD, and I've noticed symptoms of low iron whenever I stray from my very low carb diet: restless legs, low energy, ADHD symptoms getting worse. Note that iron is a necessary component for the synthesis of dopamine. Given that I take amphetamine-based stimulants, which increase dopamine release as well as inhibiting reuptake, I might need a little more iron that usual.

> Women literally lose iron every few weeks

Heh, great point.

> and many plants contain anti nutrients (phytic acid) that bind to metals, reducing their absorption, such as beans.

Also a good point, and will come back to it--

> I have ADHD, and I've noticed symptoms of low iron whenever I stray from my very low carb diet: restless legs, low energy, ADHD symptoms getting worse. Note that iron is a necessary component for the synthesis of dopamine.

Right. You make an excellent test candidate then-- is this speculative or have you actually tested your iron levels during those times?

I'd again question whether what you're feeling there might actually be a potassium/magnesium problem. You say "symptoms of low iron," and that's true in fact-- but it may only be low because you're consuming but not absorbing enough of it. I doubt you have much of an appetite.

Assuming you aren't bleeding out from gunshot trauma or menses, the next time you're feeling symptoms of what you're attributing to low iron, try eating a daily banana (or take prenatal vitamins or something).

How can it be fixed?

If I'm reading the GP correctly, by replacing kitchen items containing lead with alternatives that don't contain lead.

That should be much easier and less expensive to do than eg, replacing lead pipes in the house or town/city that may be delivering poisoned drinking water.

Is there a way to know which alternatives don't contain lead?

Just a data point here, an acquaintance of mine gave himself lead poisoning by visiting the shooting range too often for target practice. I think he wears a breather when he goes now.

Yep, also a reason why I refuse to take my children to an indoor range. Lead dust gets everywhere, I also keep separate set of shooting clothes which I wash outdoors to avoid contaminating my children's clothing.

Wow -- how often for how long were/are they going?

There was a recent study which found child blood lead levels were higher in areas with high gun ownership after controlling for socioeconomics.

https://www.hsph.harvard.edu/news/features/higher-rates-of-f...

This is definitely one of the reasons Republicans have blocked funding for gun research.

I don’t know how much their exposure was but I’d estimate they are closer to the skinny edge of the bell curve.

Maybe they had especially bad practices, like never washed their hands, exclusively eats finger food after picking through their spent bullets and licks their fingers?

Lead dust settles everywhere, gets into your lungs, especially if it's an indoor range.

Anyone who recreationally shoots ought to be getting tested for lead as part of their yearly physical.

[flagged]

Only loosely related, but are there any affordable non-invasive tests for past lead exposure?

I have a cluster of symptoms that are consistent with lead exposure[1], along with a lot of past activities involving lead (stained glass, old-school electric cars, soldering with lead-based solder, stripping lead-based paint), but my current blood lead levels are normal.

My neurological symptoms also flared up when I was supplementing with kind of a lot of Calcium and Vitamin D.

[1]mostly high blood pressure, somewhat high cholesterol (despite having normal BMI, sleeping reasonably well, exercising regularly) and demyelinating lesions visible on MRI (but no oligoclonal bands, negative AQP4).

Depends how long ago, but your hair can be tested for lead exposure. Hair grows at about 6 inches per year. If your hair was 3 ft long you could test back as far as 6 years ago with that method.

Italics mine:

>The study, described as "a wake-up call", also estimated that exposure to the toxic metal causes young children in developing countries to lose an average of nearly six IQ points each.

>Their model estimates that 5.5 million adults died from heart disease in 2019 because of lead exposure, 90 percent of them in low- and middle-income countries.

>The research also estimated that children under five lost a cumulative 765 million IQ points due to lead poisoning globally in 2019, with 95 percent of those losses coming in developing countries.

In the article, the 1 IQ point loss level is shown at about 0.25 ug/dL. I don't think this is likely in the US from brass pipe fittings containing 0.5% lead or whatever. I'm not saying that tight lead regulations are/would be bad, but this study seems to focus on the far higher disease and death burden of lead in less developed countries.

Dealing with lead exposure in developing countries would likely have large returns for the global economy, and since plenty of lead pipes were probably laid by colonial powers, has the ring of a moral imperative. But how?

Also, it makes people irritable and more hostile. so if you noticed your city becoming more rude and less polite, it may be that a lot of the people are getting borderline psychotic or personality disorder because of unenforced lead regulation violations.

There were a lot of irritable and hostile people during the Flint water crisis. Many of them stormed the capitol: https://abcnews.go.com/US/video/protesters-storm-michigan-st...

I guess that's, ah, circumstantial evidence? But yeah it's a tragedy to see these EPA violations occurring in more rural parts of the USA. What is going on with that?

Studies like these always make me wonder what the equivalent of this today. Microplastics? Carbon? What else?

Lead. It’s not gone.

And maybe some PFAS? We don’t have great data, and PFAS isn’t reliably disclosed in products. (Also, surely different perfluorinated chemicals have different effects.)

There are lead detection q-tip swab kits but annoyingly they also test positive for copper. I didn’t realize that until after I threw out a copper tongue scraper.

But I did find that one of my girlfriend’s keychain trinkets tested positive while saying “stainless steel”.

Its not gone... pretty much every single person that shoots guns need to be aware of this. Of course gun people don't care about their health and they think with their 45 ug/dL lead level that youre "overreacting"...

D-Lead is a very good company for deleading that i use obsessively, when shooting

I once called them and talked to an engineer about lead for like 1.5 hours. I think it really surprised him someone was so interested and he was happy to share.

It’s definitely a concern of mine, thanks for the heads up about that company.

For those that aren’t aware, the primer in cartridges typically have lead styphnate, barium nitrate, and tetrazene, among other things. So even if your bullets have a complete copper jacket, you still get significant lead particulate exposure, especially indoors or with a suppressor with high back pressure. No idea if whatever smokeless powders are used are doped with something fun or not. Bullets with exposed lead have additional concerns, as the surface gets flash melted/vaporized in addition to particles generated from barrel friction. This all adds up.

Never clean guns/suppressors with vinegar (acetic acid), because that just creates lead acetate, a highly bioavailabile form of lead that makes elemental lead look safe by comparison, and legally and morally requires proper hazardous waste disposal.

Fortunately there are alternatives showing up now, including some with lead free primers, but damn if it isn’t expensive, and as expected copper/zinc/mild steel bullets have trouble competing with lead for performance because it comes down to mass.

The lead acetate thing is fun to research, I went down that rabbit hole once, not because I'd ever do it but I like watching other people do it. It is called "the dip" and theres tons of videos saying DONT DO THIS but then showing you how to do it, haha. It turns bright blue or purple, I can't remember... but it's very colorful. Reminds me of the good old days of emerald green which was made of arsenic in the 1920s.

The lead jacket is always torn open and the barrel smeared with vaporized lead that comes flying out of the muzzle. There is no bullet that prevents lead poisoning in the environment. I'm a reloader/target marksman that has trapped/recovered plenty of bullets in my time.

The jacket just reduces lead fouling.

Are lead pellet air rifles even worse then? I remember cleaning the barrel of one and the cleaning tool was so very dirty.

Definitely wouldn't be worse as there will only be lead dust from erosion of the pellet in the barrel instead of additionally having lead/lead-compound vapor from the heat and chemical reactions.

But it's still a concern, so hands, arms, and face should definitely be washed after loading/shooting/cleaning. Extended firing sessions should be followed by a shower and clothes change.

Fortunately, the elemental lead in cast pellets/bullets is not very bioavailable, however it's still a good idea to minimize exposure.

Chemical pesticides, nitrogen runoff from fertilizer (particularly cow dung), nuclear waste, all the CO2 from the 300-ish years of industrial scale fossil fuel usage, hundreds of years of devastation brought onto local wildlife which drove a lot of species to extinction, leftover from bombs and chemical weapons that was just casually dumped into the ocean after WW2 [1], leftover from silicon production (a shitload of Silicon Valley is superfund sites [2]), land mines and unexploded ordnance in former fighting areas such as the "zone rouge" from WW1 [3] or what's going to be left behind in Ukraine, all the NBC weapons that especially the US and (Soviet) Russia manufactured.

[1] https://www.geo.de/wissen/forschung-und-technik/weltkriegsmu...

[2] https://www.theatlantic.com/technology/archive/2019/09/silic...

[3] https://en.wikipedia.org/wiki/Zone_rouge

PM2.5 particulates https://ww2.arb.ca.gov/resources/inhalable-particulate-matte...

Indoor gas stoves and tire dust are major problems currently.

Pretty much anything our ecosystem hasn't had time to evolve and adapt to is likely going to have some deleterious effect on the life forms within.

TikTok?

Social media has caused the largest brain drain we've ever seen.

> Carbon

could you elaborate?

Probably referring to climate change / global warming. Carbon dioxide doesn't kill people by itself, but it can trigger floods, droughts, heat waves, etc. that will harm human habit.

Oh, I though probably the carbohydrates... Sugar kills!

Even american eagles are increasingly dying of lead poisoning.

https://gasanature.org/bald-eagles-across-the-us-are-being-f...

Lead found in the bullets of hunters, who tend to hunt larger game like deer, poison the meat of the deer. Once the lead enters the gastrointestinal tract, it becomes toxic. If the deer runs and can’t be recovered by the hunter, it typically will die and be consumed by scavengers – like the bald eagle.

"For example, the relationship between lead in blood and heart disease is based on a survey"

What, just a survey? What is the mechanism that causes this? Heart disease is a major killer, but I assume most of it is due to lack of exercise and terrible diet.

And lead is still allowed in aviation fuel. The planes (only piston?) are spraying it all over you every day.

It's being actively phased out. The replacement for 100LL was literally just approved by the FAA a year ago, after decades of work.

Many of the bay area airports have already started offering 94UL unleaded fuel, and the others across the country are likely to follow suit shortly.

Is this actually true? I think that’s changed. Also - how much of a problem is it? What kind of lead exposure do I receive from a small airplane flying over me one day? What does this risk compare to, say, smoking? Or not wearing my seat belt?

Simply stating that a bad thing exists is not enough.

It's true, but that's because there was no legally approved alternative until about a year ago.

Now that there's an approved unleaded replacement for 100 Octane avgas (G100UL), I expect leaded fuel will disappear quickly. Airports are currently in the process of installing the new tanks to dispense it.

Many of the bay area airports already started offering unleaded 94 Octane (UL94) at the pump as of earlier this year.

(Pilots don't like leaded fuel any more than anyone else. It's way too easy to get on your skin during a preflight check. We really want it gone.)

Yeah I always used to get it on my skin doing the drip check with those shot glasses with a pin in it. Yuck. Does it get absorbed through the skin?? I never knew and I usually didn't wash my hands because there was no toilet nearby, airside.

The TEL in liquid form is probably much more toxic than metallic or inorganic lead you find in stuff like paints or bullets due to it being more lipophilic and bioavailable. Be very careful with leaded fuel.

Ahhh, ok, that must be what I remember reading, thanks.

According to this, it is. https://en.wikipedia.org/wiki/Avgas

edit to add: I suspect a small plane flying over you one day is no problem at all, but there are many general aviation airfields very close to places where people live and work.

There have always been people on this site who think RoHS was a conspiracy. There are a few people who do not take the public health problems caused by lead very seriously.

And you can't, with a straight face, tell me that lead free solder matters, while we're still using lead acid batteries with dozens of pounds of lead in every car out there (to within a rounding error, and, yes, it includes almost all EV/PHEVs). The list of exemptions is very long.

Lead free solder is objectively worse as a solder for just about any metric related to longevity. So you have to weigh the risks of lead in solder against the reduced longevity of entire electronic devices from solder joint failures. Lots of BGA components have had problems related to their solder, and the usual result is that the entire device gets thrown out.

Lead free solder is fine. When RoHS was first implemented, a lot of manufacturers had trouble changing their processes for the new solder. The result was a plague of bad, broken solder joints.

Nowadays, lead free solder is accounted for starting in the design stage. Manufacturers have had 15+ years of experience with leadfree solder and have largely worked out the issues.

Lead-acid batteries are extensively recycled. Electronics are usually just dumped in the trash, making the lead issue much more important.

>while we're still using lead acid batteries with dozens of pounds of lead in every car out there

Mostly those cars stay outside and the batteries tend to be expensive and highly recycled, electronics on the other hand, show up everywhere and have a poor history of recycling.

Battery retailers will pay you $25 for the old one and even if you just dump it, desperate people will collect it and hump it down to the recycler to get the core refund.

Nobody wants your old soldered electronics. That stuff is nothing but trash.

All of the battery retailers around where I live (southern Indiana, USA) stopped paying for old lead-acid batteries years ago. Only the local scrap metal yard still pays for them, and they only pay $5 per battery. People only bring in their old batteries for recycling because it waives the core charge.

You just contradicted yourself. The core charge is them paying you for the old battery.

Batteries are recycled, check it out:

https://www.youtube.com/watch?v=kNGg0P7B5fI

I have a conspiracy theory that people recommending leaded solder (And reacting hostilely to suggestions it may be dangerous) are demonstrating the effects of lead exposure.

I don't buy the "just wash your hands" argument.

I don't think leaded solder is dangerous to the home hobbyist, provided reasonable precautions are taken (no food, drinks, or smokes on the bench and wash your hands immediately upon getting up from the bench).

If you're repairing something that used leaded solder, you pretty much have to use leaded solder. That's fewer and fewer things post-RoHS, but when you have something older, you're going to use leaded or you're going to have a bad time.

With a decent iron and flux, hand soldering with lead-free solder is fine. All my new work is lead-free, but I have zero concerns having my kids work with leaded solder at the frequency and using the reasonable precautions.

Leaded solder isn't a problem to work with, it's a problem when it contaminates landfills.

Also the supply chain: smelting and refining. Herculaneum Missouri has acres bulldozed of what used to be homes once they learned the children were born with lead poisoning. Before the dozing citizens put up warning signs telling people to take off their shoes when they got home and not to let their kids play in the contaminated public spaces.

In the last year, how many tons of lead ended up in solder?

And how much has gone into fuels (especially aviation fuel)?

The EPA estimate for avgas is roughly 500-600 tons of lead annually (depending on the exact estimation factors used).

I found an estimate of lead from e-waste (all sources of lead, not just solder) being 58,000 tons per year, roughly 100x the avgas figure.

Recently read that sweat concentrations of heavy metals can be about 7-8 times higher than blood serum levels. So you can sweat out heavy metals, but just barely. My guess is you lose more in skin flakes and hair.

Does anyone know the the risk is for electronics hobbyist?

Don't lick your boards, wash your hands before you eat, and if you're really concerned, wear gloves while handling solder wire.

The smoke from soldering isn't lead - a soldering tip is (if it's not literally glowing into the yellows) far, far too cold to vaporize any lead from solder - you need to be 1500+C for it to start being a problem, and you're not soldering that high. It's rosin smoke, and if you're in doubt, leave your iron in a puddle of solder - it shouldn't smoke, it should just sit there liquid after the initial rosin has burned off.

The rosin smoke isn't great, but it's not a lead toxicity issue.

Your concern is lead on your hands from the wire, and then eating afterwards without a good scrubbing. I don't think it will penetrate your skin, but you could always wear a pair of gloves if you wanted. There are some shooting sports soaps that are designed to help really rip any lead off your hands, so you might use one of those if you're concerned.

Also, afaik, there's no reason for hobbyists to not always use lead-free solder. But of course that doesn't mean something you're taking apart used lead free.

The leaded solder melts easier than non-leaded. This is good because you are way less likely to burn off traces or melt the board using a lower temperature iron. I only use leaded solder because I suck at soldering.

Repairing an old device that used leaded solder is a reason to use leaded solder (even new leaded solder during the repair). I don't even use the same tips across leaded and lead-free solder.

I think pretty much all consumer electronics uses lead free solder for the last 10+ years. The reason hobby users tend to use leaded is it's much easier to work with and they don't care about health or the environment that much.

A few years back spent a lot of time stripping lead paint using a heat gun and IR emitter thing ("silent paint remover"). It was definitely smelly, but I convinced myself that the temperatures were far too low to vaporize lead.

But in the back of my mind I always wondered if there was an equivalent of a eutectic mixture for the liquid/vapor phase transition.

There are. They are usually called azeotropes. For example water and ethanol form an azeotrope, though the difference isn't as drastic as with metals.

Soldering doesn't get hot enough to make significant lead fumes (although flux fumes are also bad to breathe). The main risk from lead solder is from cleaning your soldering iron. Both the common techniques (damp sponge and brass wool) make many tiny balls of solder. They can be hard to see, and because they're round and dense, they can travel much farther than you expect by rolling and bouncing. They can get caught in clothing, and from there potentially fall into food.

I don't personally use lead solder for this reason. If you have a good temperature-controlled iron then SAC305 is almost as easy to use.

I typically use lead-free solder unless I'm dealing with some annoyingly massive thermal mass like a joystick anchor, but I use the same rule whenever I'm dealing with solder, fishing weights, and ammo: wash hands before they go near my face after handling lead products. Inorganic lead is not readily absorbed through the skin (that's not to say it cannot be, or never is), so generally speaking as long as you avoid ingesting it (hence wash hands after handling it) there's little to worry about.

Unless you're dealing with electronics made prior to 2006, almost all of what you'll be soldering with is lead-free. Thank the EU's RoHS directive for that.

[1] https://en.wikipedia.org/wiki/Restriction_of_Hazardous_Subst...

There's a lot of argument that lead-free solder isn't as good (or easy to use) and several hobbyists still use leaded solder.

Have you ever tried the lead free stuff as compared to a good 60/40 or something like that?

It's horrid to use. And the lead-free stuff is far worse in manufactured equipment - how many devices have failed early due to BGA solder joint failures that basically didn't exist before RoHS requirements? I think the nVidia 8600M issues were traced to that, and plenty of other BGA equipment since 2006 or so has failed rather early.

Solder comes in many different alloys. Some of them are really terrible. However some of the better ones are pretty good. Spend some money to find a good one. If you can find a manufacture they often have a lot of data and will tell you which is good for what. Often bad solder is great for some purpose, but that purpose may be something not useful for you (you probably don't need the maximum strength joints as one example), cheap while still working is useful at industrial scales, but odds are $75 of the most expensive solder will outlast your lifetime so why cheap out?

It's only horrid when the flux it comes with is crap. Most people try the cheapest garbage they can find on Amazon, and that's the problem.

I use Chipquik SAC305 with water-washable no-clean flux core and I actually prefer working with it over Sn63Pb37.

Yep, I was around for that shitshow with two laptops. Soldergate was annoying but to be honest there haven't been any similar issues at scale I'm aware of, as the issue was identified and fixed.

Your hobby really isn't worth breathing lungfuls of leaded-solder fumes. Manufacturing is done by robot, not you sitting over a desk (said as someone who was doing this till I realized it myself).

Lead-free solder can be a bitch to work with for some projects due to the higher melting point, and I do keep a spool of leaded wire around for that reason - but generally speaking for most hobbyist uses it's a non-issue as long as you have a relatively modern iron that can output enough heat (and retain it).

Yeah, a good iron and wire with a decent flux core helps a lot. Lead-free solder will never melt like butter the way leaded does, but I solder with it fairly often at work and it's not a show-stopper by any means.

Flux in general is probably the most important right after making sure you have an iron capable of handling the thermal recovery (you can't get the shit to stay liquid long enough if your iron can't handle keeping temp). The difference between relying on the flux core in even my leaded solder and adding a tap of my MG Chemicals flux when making a joint is night and day.

My lead-free joints come out nicely rounded and shiny just like my leaded ones with some practice and the right consumables. But I certainly have to break out hot air station more than I would when using leaded solder to deal with larger thermal masses (and why I will still break out my spool of leaded wire on rare occasion when I'm working with temp-sensitive components and just want it on the freaking board).

Yeah I use lead free for some stuff. I have switched back to lead for finer work since it just behaves better. Seems like the sweet spot for lead free is very small - too cold and you get a weak dome connection, too hot and it doesn't want to leave the tip.

Was hired as a software engineer at a tiny company, in April of this year, that produces surveillance cameras. They had me building and repairing their cameras which involved a non-trivial amount of soldering. They never told me I was handling lead and I wouldn't have known if I wasn't a curious person but it turns out they thought lead-free solder "sucked" and wouldn't switch.

Not nitpicking but solder for military and public transport applications is exempt and still used, due to better performance under vibration and shock.

considering almost all of this is in poor countries i'd say you are low risk if you solder infrequently and always have good airflow. that said there's no safe level of lead so wear a properly fitted p100 respirator if you want to be as safe as you can be.

None if you use quality lead-free solder.

Unfortunately lead-free solder is a lot harder to solder with; it just doesn't flow as nicely. Companies doing it in an automated way have long figured it out though.

This is why hobbyists are often still using leaded solder, particularly outside of the EU. But also in the EU, because it just flows so damned nice.

That's not actually true though.

I find SAC305 to wick into joints faster than leaded solder does, provided you have quality flux in the solder.

If you get the cheapest lead-free solder you can find on Amazon it will be bad.

Doubly so if you have a non-temperature-controlled soldering iron. Too cold, and it won't melt effectively. Too hot, and exposed metal will oxidize rapidly.

provided you have quality flux in the solder

which you often don't need with leaded solder.

Yes, you need slightly better flux to avoid using toxic heavy metal in your hobby electronics.

What is your favoured temperature for let's say through hole DIP connections?

650°F or 340°C.

Works beautifully with SAC305.

I count five uses of the word "estimate" in the method section and I didn't even copy the entire thing.

In this modelling study, we used country blood lead level estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. We estimated IQ loss (presented as estimated loss in IQ points with 95% CIs) in the global population of children younger than 5 years using the blood lead level–IQ loss function from an international pooled analysis. We estimated the cost of IQ loss, which was calculated only for the proportion of children expected to enter the labour force, as the present value of loss in lifetime income from the IQ loss (presented as cost in US dollars and percentage of gross domestic product with a range). We estimated cardiovascular deaths (with 95% CIs) due to lead exposure among people aged 25 years or older using a health impact model that captures the effect of lead exposure on cardiovascular disease mortality that is mediated through mechanisms other than hypertension. Finally, we used values of statistical life to estimate the welfare cost of premature mortality (presented as cost in US dollars and percentage of GDP).

Some of you might be interested in https://leadelimination.org/. Currently 100+ countries have no lead paint legislation. LEEP work to ensure effective policies and eliminate lead poisoning globally.

(I have no affiliation beyond having chosen to donate)

Is IQ a piece of private information?

Does everybody in the country get an IQ test in school? Can we just look that up in the public records?

It sure would be useful if it was public and universal. For tracking the effects of lead poisoning for one. Or just factoring it into any big study. We might find something unexpected.

IQ being public might be problematic; I've heard from more than one lawyer that one ought-not use IQ as a hiring filter, unless you have evidence that the IQ test is not biased against any protected groups.

Indeed, hiring from more selective universities is, to a certain degree, a way of laundering hiring based off of IQ, since you can pass the buck to the university itself to not be racially biased.

This is a common predicament.

A piece of information that, if it was made public, would be immensely useful in countless ways for the management of our society, But it might also be exploited by bad people. So it is made private.

And the icing on the cake. We say "it's private because privacy is intrinsically good and a basic human right ". Not, "It's private because we fear bad people".

>would be immensely useful in countless ways for the management of our society,

Such as?

Now, maybe if one person had an IQ of 80 and the other contender had an IQ of 105 it seems like it could be useful in some particular fields. But for the most part you'll run into the "I'm 200 times smarter than you because my IQ is 102 and yours is 101".

And there is no icing on the cake. Privacy is a multipolar topic and there are many pros and cons around it.

We have rights not because they are some intrinsic part of the universe, or inalienable text written by a deity, we have rights because people working together and learning from the past mistakes in history have decided that something better than what was is attainable, and the moment we forget it something worse will take its place.

If all of the IQs in a county went down we might investigate that. There's one.

If we were looking for smart people for a role in whatever. There's another.

If we were rating schools. There's a third.

Gee, my imagination is feeling so stretched.

> If all of the IQs in a county went down we might investigate that. There's one.

The average is always by definition exactly 100, neither higher nor lower.

Also, this data already exists. The folks who make standardized tests collect it to use for translating raw results to standardized scores.

> If we were looking for smart people for a role in whatever. There's another.

This is illegal. There are ways to get the same result that are not illegal, and are actively used.

> If we were rating schools. There's a third.

Schooling doesn't do much to iq.

> > If all of the IQs in a county went down we might investigate that. There's one.

> The average is always by definition exactly 100, neither higher nor lower.

The average for the population that the test is normalized is exactly 100. GP was suggesting that if the averaged dropped in a single locality (specifically county, but I'm generalizing), which is completely possible.

> "It's private because we fear bad people"

I wonder if the thought process even goes that far. Oftentimes, the motive seems more like self-conscious social pressures, e.g., fear of embarrassment.

Or even just fear. A rationalization of anxiety.

A chronic ubiquitous anxiety "rationalized" as a fear of everybody for everybody.

Try posting the question on social media sometime. The answers are interesting.

In general, if you are using any test in your hiring that does not relate to the job responsibilities, you are not allowed to use a test that doesn't have equal outcomes for any protected class.

There are some races with average scores of 70. Can you believe it?

Why of course I am talking about "white america" in 1900s [1].

[1] https://www.apa.org/monitor/2013/03/smarter

> Over the past 100 years, Americans' mean IQ has been on a slow but steady climb. Between 1900 and 2012, it rose nearly 30 points, which means that the average person of 2012 had a higher IQ than 95 percent of the population had in 1900.

People really don’t like when they get called out for their bigotry, huh? :thinking:

Goodhart's law strikes again.

As soon as IQ becomes a measurable thing, populations that measure it will act in ways that increase it. Shocking, I know.

It's interesting how closely tied "goodness" and "intelligence" are.

To make a mistake is to be a bad person. To be stupid is to be bad.

I can call you weak. I can even call you ugly, cowardly or a flibbertigibbet. But if I call you stupid look out!

Like our whole worth as humans is summed in our ability to talk smart and solve riddles like a trained animal.

Which seems pretty stupid.

> I can call you weak. I can even call you ugly, cowardly or a flibbertigibbet. But if I call you stupid look out!

This might be a bit peculiar to the HN crowd; calling someone cowardly is fighting-words in many groups.

I've thought about this a lot and I think there's a reasonable hypothesis in evopsych (I know, I know...):

If you're making material mistakes that hurt the social group you're in, especially things that cost extra work for someone else to undo and redo correctly, then you could be identified as someone ripe for removal from the group. Ostracization means assigning taboo or outsider status to that person, either as a way to get them to shape up and earn back the trust they lost or to remove them entirely with little remorse.

It will seem even stupider once computers can convincingly do all the "intelligent" things better than us.

In fact, they can already seem smarter, even when they're not.

Maybe we can move on to prioritizing humans on other criteria -- like how nice they are to each other, how good they are at making nice art, or skiing an amazing line down a mountain, etc.

Indeed, except that IQ has not became a thing to optimize for, and even if it was, there are no known ways to increase it.

There is one way:

https://gwern.net/embryo-selection

Education and QoL seem to be correlated.

IQ is only useful for scores well below average to indicate the subject of the test has a serious issue. Any score approaching average or any amount above is not at all useful to indicate anything beyond the subjects' skills at taking IQ tests. It translates to and indicates nothing compared to another mostly average or above score. Psychologists (mostly) want to scream abuse at you about pointing this out. Then have steam shooting out of the ears when you bet them your IQ is higher than theirs and that also, in itself means nothing. There's no magic formula or spell that let's you understand a human faster, better or more accurately than spending the time talking, reading and listening to what they've done and what they think. There is no way to make it objective.

IQ is so much bullshit. Probably why it turns up so often in racist screed masquerading as science. Burn it all down.

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It's almost as if circumstances matter and we should be looking for ways to improve :thinking:... I don't think anyone would classify white people from the US from the 1900s as mentally handicapped but, well, at least someone else said that and it wasn't me.

> Over the past 100 years, Americans' mean IQ has been on a slow but steady climb. Between 1900 and 2012, it rose nearly 30 points, which means that the average person of 2012 had a higher IQ than 95 percent of the population had in 1900.

And if the public (sometimes even people in academia)'s reaction to any data they don't like is outrage, how could we look for ways to improve anything?

reminds me of those comic where the adult explains to the kid that every physical attribute was explained by genetics

and then stumbles over his words trying to explain cognitive ones as inherently different

was just a funny perspective I’m not trying to start a pogrom with this observation

If we neutered everybody who scored under 130 IQ, what do you think society would look like in 3 generations?

It'd collapse from underpopulation and there'd be no guarantee that the survivors would be any smarter because "smart genes" interact in complex and nonlinear ways - if they didn't we'd have already evolved to a point they did due to the strong selective pressures already acting on us.

Anyone worried about lead should take calcium pills with vitamin D which helps absorption. Calcium should always be taken with food otherwise your body just ignores it. It works because your body interprets lead as calcium.

You mean calcium reduces lead absorption?

Edit: Ah, vitamin D helps calcium absorption, which then reduces lead absorption.

This is why I stopped eating paint chips.

Some of my bloodwork revealed subclinical lead poisoning. Part of the investigation was to take the dirty A/C filter in for lab analysis of the dust. I had lead in that filter, so I moved out. No idea where it came from.

EDIT: It was an apartment. FWIW, even new apartments can have other issues, like a brand new place my friend was working on had rampant mold issues (built & exposed throughout monsoon season). So you really have to be careful.

Who bought the place after disclosing airbourne lead dust in the house?

If it was a rental, GP would never know who moved in next. (I would describe leaving a rental as "moved out" and leaving a house I owned as "sold it". Given they used "moved out", I'd wager even-money it was a rental.)

In california if you sign a lease for a building built at least 20 years ago you probably get a boilerplate lead warning document as well. Its like a prop 65 situation where so many things are labelled that the label itself loses meaning.

Soils in many major US cities can have high amounts of lead. If you're not controlling how much dust is tracked in that very well could be detected.

Perhaps OP had a rental with an in-unit AC unit which is pretty common here in the US.

It was an apartment with central cooling.

if you are renting (in most / all? of the US), no way the next person would know.

Perhaps significant enough vaper from plumbing solder made it into AC unit or some other building or trade technique which involves some lead

Plumbing solder is overwhelmingly lead-free and has been for years. Even if leaded solder was used, the vapors from soldering are flux residues, not lead.

They used number from a 2019 Global Burden of Disease study as one "axis",

How did they prove the causality of various conditions to the study?

Deviations from a normal distribution?

Existence of Karens might be just a symptom of lead induced brain damage in the entire generation or two.

Is it possible to measure amount of lead in water somehow at home?

Yes.

The easiest method is "at home" strip tests that react to various concentrations. eg: (in Australia)

https://www.alloratestkits.com.au/shop/lead-water-test-kit/

Available from a number of companies | countries | international order.

From there it's a matter of chemistry and what kind of equipment you might have or be able to access via a local school or friend from the test tube crowd.

Or bottling a small sample of your water and sending it to a local | state lab for testing.

DMSA, which is the treatment for lead poisoning, is cheap, can be taken orally and has a good safety profile. Shame that doctors are not more familiar with it.

Doctors certainly are familiar with chelation therapy (like DMSA) as a treatment for heavy metal poisoning (like from lead)

Since taurine can be used to chelate lead, I propose everyone drink a lot of Monster.

what I'm hearing is that if I already have 5μg/dL, then I might as well get all 20.

epic water filter + nalgene 32 oz hdpe bottle is a great, lightweight filtered drinking water on-demand system

filter pitchers are easy to use and a good safe guard against poor plumbing if you haven't had your home water tested

HDPE Nalgene bottles probably leach PFAS:

https://www.reddit.com/r/Nalgene/comments/wqdgbi/are_nalgene...

Glass or stainless steel would be a better choice (especially for storage).

My old bottle with this same filter was glass, but it was very heavy and it also ended up shattering when I was climbing a mountain and lost my balance and had to toss it onto a nearby ledge. And the filter itself filters a lot of pfas and other microcontaminants.

"That's why we've taken a layered approach, incorporating a variety of high-performance filter media into one powerful filter. Crafted and rigorously tested in the United States, this multi-layered filter is engineered to effectively target both tap water pollutants such as chlorine, microplastics, lead, PFAS, and more, as well as outdoor water contaminants like bacteria, viruses, and microbial cysts like cryptosporidium and giardia."

And the lid and straw itself is also made of plastic. Life is hard and something is better than nothing.

Your own citation contradicts you.

Nalgene bottles are now made exclusively from polyester, which is not subject to post-process fluorination, and even if it were, there would be no reason for a company to spend the money to fluorinate consumer water bottles.

Whats my risk of exposure to lead from improperly made glass or stainless steel?

Stainless steel could easily contain quite some ppm of lead. Metals are frequently recycled, and hard to separate.

Glass could also contain lead in contaminants - but actual metallic lead won't end up in the finished product - but lead oxides might well.

Having said that... There are probably many devices in your house or supply chain which deliberately contain lead in double digit percentages. Worry about those before worrying about contamination.

> Having said that... There are probably many devices in your house or supply chain which deliberately contain lead in double digit percentages. Worry about those before worrying about contamination.

I cycled pulverized lead paint around my alveoli as a kid doing construction and used to bite lead fishing weights when I was very young to make sure they stayed on the line.

Thankfully it is now stored in my skeletal system for future use by my nervous system.

Applied Science has made a recent episode about this topic: https://youtu.be/-cAB5FG4bXI

("Measuring the amount of lead (Pb) consumed when drinking from lead crystal glassware. Is it safe?")

Micro plastics in the Nalgene, especially if it’s exposed to any sort of heat.

There’s no BPA, but there have been “cousins” of BPA created that essentially are just as, if not more, harmful

It is my understanding that the common filter pitchers don't filter out lead.

That's not correct. It depends on the water filter. A common Brita filter doesn't filter lead. But the referenced filter (Epic) does. There are other filters that can do that, the most popular is ZeroWater, which you can check their datasheet https://www.zerowater.eu/wp-content/uploads/ZeroWater-NSF-ce...

Be dubious of those claims. Lead can be in hundreds of chemical compounds. I very much doubt they have tested the filter against all of them.

Only reverse osmosis will do a decent job of removing lead, and even that won't be perfect.

The problem with ZeroWater is it filters out everything. I would be always thirsty after drinking from ZeroWater, it was a weird feeling.

So then you have to remineralize it...

But how are those minerals being sourced, and does that mixture contain lead? Ugh, it never ends.

So is IQ a "largely pseudoscientific swindle" to quote a popular article from a few years ago, or is it not? Because if the consensus is that it doesn't matter, then why bother using it as a metric here?

It's complicated. Firstly because there are a lot of "IQ studies" that cited in places such as The Bell Curve that had utterly horrendous methodology. Second because there is a lot of cultural baggage around the very concept of IQ, as if it were a measure of someone's intrinsic intelligence rather than just measuring the result of the combination of intrinsic and environmental factors.

I think it depends on the scope of what's being addressed as "IQ". As far as I know, there are some fairly robust methods and results around IQ, but it's usually hard to make the leap from those to a sales pitch for any particular product/service/policy/program in a similarly robust way. So any given invocation of IQ in the wider world has a high likelihood of being somewhere between scientifically sketchy and outright nonsensical. It's reminiscent of quantum mechanics and epigenetics in that sense.

Yes and no. IQ isn't useful for saying anything about a particular person. However it is a consistent measure so if one group tests different from a different one we should suspect there is something wrong and look deeper.

Well below average IQ scores usually indicate serious and profound cognitive impairment (but for an individual you still have to check).

All other IQ scores indicate nothing at all.

It’s not that binary. IQ is like any other statistical measure of human characteristics - it’s very nuanced.

The IQ tests measure something and we can correlate that thing with other aspects like academic performance, other test scores, income, wealth, etc.

It’s a useful comparative metric, but it is not useful when people try to use it for things like racist bullshit.

Do you have another suggestion? Many of the criticisms of IQ seem less relevant in this context.

It's about as legit as height. Does it matter? Not really, but it correlates with a lot of interesting stuff.

People are more inclined to believe in something when it supports their cause.

taleb's argument has changed to IQ only matters for downside, not upside.

Not changed, that's always what the article he was referring to said.

Question for any IQ skeptics here (e.g. "it just measures your ability to take tests" or "it just tells you how rich your parents are"): what's your response to studies like this? Is there anything that can be said about the effect of lead on cognitive function? Why might IQ be a good measure of lead-induced stupidification, but unreliable for literally anything else?

I think it's a pretty straightforward thing: intelligence somewhat correlates with life/career outcomes overall, and it's not linear. Separately, IQ tests are reasonably good, though imperfect measures of general intelligence. Also separately, if you look at careers where high intelligence is needed, then IQ correlates much better.

IQ does not principally measure test-taking abilities or SES. Yes, those correlations exist, but their effect sizes are not nearly as large as a certain political ideologies would have you believe. And simultaneously, it's not as ironclad as the other political ideology would have you believe. It's very reliable as these things go, but noisy at the margin.

EDIT: a sibling comment correctly points out that aggregate effects do not always apply individuals.

It's possible for IQ to be a good population measure while being a poor individual measure. (FWIW, I think proponents and opponents of IQ testing all overstate their cases.)

I assume the study authors controlled for such things. For example, they could bin the study participants by socioeconomic group, race, location, etc, etc, etc, and then show the average IQ loss per bin.

I haven't read the study, but statisticians do this stuff for a living, and there are definitely ways to control for sample biases that let you distinguish between "poorer people have lower IQs and are exposed to more lead, and the root cause of both is being poor", and "lead leads to lower IQs within all socioeconomic groups we could think of and measure"

But these controls could be done for any IQ-related study. Is IQ-skepticism based on the belief that IQ researchers generally don't use controls? That lead-IQ researchers alone do this?

You can't demonstrate causation by controlling for things, because of collider bias.

https://en.wikipedia.org/wiki/Bad_control

You need better methods like an intervention study or a natural experiment to show causation.

Most IQ skeptics think IQ correlates with intelligence. The argument is generally over how good a proxy it is for intelligence and what conclusions can and can't be drawn from statements about IQ

False.

Low IQ correlates with lack of intelligence. Average and above means nothing.

--IQ skeptic

That's still a loose correlation, but I do appreciate the correction

Intelligence is both directions. It only correlates with un-intelligence. Eg the poor individual has a brain injury or does not.

If the chemical can complete nullify the advantages of having rich parents, how doesn't it sound bad enough...?

You have to read the study to find out what it meant by IQ. People freely confuse IQ (a score on a test that's calling itself an IQ test) with IQ (a platonic ideal statistic people assume exists for the purpose of publishing research about it). This could be either.

Sorry, is your criticism that IQ proponents conflate point estimates with unknown population parameters? Is that what other IQ critics see as the core of the disagreement in this debate?

Well I don't want to speak for anyone else.

It's more of a secondary criticism though, that people aren't very careful about reading research papers. And of course that in many fields the researchers aren't careful either (https://en.wikipedia.org/wiki/Credibility_revolution).

The primary criticism is that people want there to be something called IQ (or g, or intelligence) that is 1. a real physical variable that causes things 2. an unchangeable attribute of a person that 3. makes you better and more virtuous than people with less of it. This recently causes 4. the belief that if we invented an AI it'd have a lot more of it than us and would take over the world[0].

Whereas I think that:

1. the best reason to know it is to find working interventions to improve it, which they can't find because it isn't real, so they should find some real physical processes.

2. the other reason to know it is to predict someone's ability on a task, and in any such situation there is better evidence you could use for that. Although this one's kinda illegal anyway (https://en.wikipedia.org/wiki/Griggs_v._Duke_Power_Co.).

3. a superintelligent computer would not take over the world.

[0] The Lesswrong guy, the main advocate of this one, didn't graduate high school but would like to be seen as intelligent, which means it's convenient to believe that intelligence is so inherent you don't have to prove it by performing well at school.

No, IQ is just the test result; the theoretical phenomena understood to be underlying it are things like g and task-specific factors.

You're claiming this study used a test that it could have a "the test result" for, but it didn't - it's a meta analysis using another meta analysis, whose different studies all used different tests:

https://www.thelancet.com/journals/lanplh/article/PIIS2542-5... <- the one in the article

https://ehp.niehs.nih.gov/doi/10.1289/ehp.7688 <- the one it refers to

> We contacted investigators for all eight prospective lead cohorts that were initiated before 1995, and we were able to retrieve data sets and collaboration from seven. The participating sites were Boston (Bellinger et al. 1992); Cincinnati (Dietrich et al. 1993) and Cleveland, Ohio (Ernhart et al. 1989); Mexico City, Mexico (Schnaas et al. 2000); Port Pirie, Australia (Baghurst et al. 1992); Rochester, New York (Canfield et al. 2003); and Yugoslavia (Wasserman et al. 1997).

I checked two of the studies from 1989:

https://www.sciencedirect.com/science/article/abs/pii/089203...

> The test used was the Wechsler Preschool and Primary Scale of Intelligence.

https://www.nejm.org/doi/full/10.1056/NEJMoa022848

> We measured blood lead concentrations in 172 children at 6, 12, 18, 24, 36, 48, and 60 months of age and administered the Stanford–Binet Intelligence Scale at the ages of 3 and 5 years.

So they didn't all take the same test[0]. This supports my claim, which is that people who believe IQ research also believe that all test results produce the same valid statistic called IQ as long as the test calls itself an IQ test.

I actually can't think of a time I've seen an online IQ arguer claim that any given test result isn't an accurate representation of an IQ. They certainly also think it about things like SAT scores and old national-IQ studies where they gave the tests in second/third languages or just made up the numbers.

[0] if it was the same test, isn't the norm process to convert from raw scores to normally distributed ones be different in different years? Not sure how that part is done.

I think IQ reflects your general cognitive ability AND a few other things like wealthy parents etc.

Just like your videogame score reflects your diet and a few other things.

Just like lots of things.

> "it just measures your ability to take tests"

This is largely wrong. One could be a master at test-taking and not come close to a high score.

That said, familiarly with the test/item structure almost certainly helps, especially for folks with the potential to score high (see below).

> or "it just tells you how rich your parents are")

Hmm… family wealth and IQ may be correlated, but not perfectly so. There are plenty of low-IQ rich people and also plenty of high-IQ poor people.

> what's your response to studies like this?

Probably too many confounding variables. That said, this study is a publishable unit that can push one or more funded agendas, so here we are.

> Is there anything that can be said about the effect of lead on cognitive function?

While I know a bit about IQ, I don’t know much about the details of the relationship of IQ and lead.

> Why might IQ be a good measure of lead-induced stupidification

Maybe it’s not. See “funded agendas” comment above.

> but unreliable for literally anything else?

(the main reason I replied is below)

People really need to let go of this idea in a reasonably reliable way.

1. IQ measures reasoning ability. It is quite good at measuring this.

2. People put a lot of weight onto how IQ correlates with a bunch of other things, but these are not things that IQ tests are designed to measure. As such, these correlations may not be meaningful in some cases. So the “literally anything else” that IQ is allegedly not good for is almost entirely things that IQ tests are not designed to measure. I don’t think it’s prudent to disregard the test/measure because of misuse by some folks (typically within agendas).

3. People get very self-conscious about IQ scores. Let me help with that. IQ scores are a measure on a particular day that can vary from day to day for any one person. For any given test taker, they are trying to optimize what they score out of a theoretical max (i.e., their “true IQ”). Many, many things cause people to score lower than their potential max — lack of sleep, lack of food, external distractions, distress (physical, mental, emotional), anxiety, ambivalence, lack of test familiarity, etc. Very few things cause them to score higher than their max (it will almost certainly be within the confidence interval). It’s ok. Retake the test if it matters (it usually doesn’t).

4. IQ matters most in three areas, imho. The first is at the extremes. Gifted/genius folks and learning disabled folks need additional resources. How and whether this is implemented is highly debated. The second is in leadership positions. You want your leaders (e.g., in the military) to be within about 20 IQ points of those they lead. The idea is that > 20 IQ delta folks see the world in fundamentally different ways, so leading someone who views the world so differently is difficult and largely inefficient. The third is with one’s significant other. Same as above, it will be hard to be understood (if that’s your goal) by someone who is +/-20 IQ points away from you.

I hope this helps.

Dude, you are spewing out random things as if they are fact. Yet you lack an understanding of what IQ is.

IQ is an attempt to measure a general intelligence factor (g-factor). What happened is that researchers noticed that people who are good at some tests tend to also be good at other tests, even if it's from very different domain. E.g. say you are good with math, you also tend to be good in you language skills. This led to the assumption that there is a general factor out there that is shared across all skills (the g-factor). So determining how good you are at math is a combination of your math specific skills + the g-factor. Same with other domains.

How do you extract the g-factor? You measure a large set of people across a cognitive challenging set of tests, and do a factor analysis (statistical technique) to extract a linear g-factor. Each test can have a "g-loading" which essentially calculates what portion of it is due to the general g-factor. For example, one of the tests with the highest g-load is simply hearing a sequence of numbers and repeating them in reverse. This test has nothing to do with "reasoning skills. Yet for some reason you claim that it's designed to measure reasoning skills but not designed to measure "a bunch of other things".

You also claim that IQ varies significantly day to day, but that has not been shown in studies. In fact, IQ measurements tend to be remarkably stable across the person's entire adult life.

Than you spewed up a bunch of unsubstantiated claims about the difference of IQ between a leader and his team.

> Dude, you are spewing out random things as if they are fact. Yet you lack an understanding of what IQ is.

In my previous career, I did quite a bit of research on IQ. I’m pretty sure I have a decent understanding of what it is.

If you take out your straw-mans and overstatements of what I said, then I think you will be able to find research that supports everything I said above about IQ approximately to the degree of confidence that I stated it.

Let’s make it easy - please cite the research that shows that an IQ gap of 20+ leads to worse leadership results.

> Let’s make it easy - please cite the research that shows that an IQ gap of 20+ leads to worse leadership results.

Iirc, Greatness: Who Makes History and Why cites some research on this very topic.

There is more to be found — I’m sure you can find it if you try yourself or ask a librarian at a good academic library.

I will also add that you have conveniently ignored the fact that I prefaced that specific section with “imho”. It’s my opinion, and I stated all of those comments as such because I don’t think that there is any unassailable research in this area. There probably won’t be due to the difficulty of structuring a good and replicable study regarding IQ and IQ deltas specifically.

While the overall research is not air tight, there is research that I have done (unfortunately proprietary) that indicates that the “20 IQ point difference” concept is directionally correct (“directionally” because we had to use IQ proxies). Implementing this in organizational restructuring led to consistent measurable improvements at the extremes (which was our focus).

Given your challenging tone and style of engagement, I’m guessing that you’re hellbent on flaming. I’m not interested. As such, I will leave you to your library and librarian to find research that supports the ideas I have stated (assuming you bother to look).

“Leadership and IQ delta” a super interesting topic, but the current trends in psych research and psych funding unfortunately don’t really focus on these areas despite demand from outside of academia (it’s very political in an uninteresting way).

Best of luck!

The reality is that it’s very difficult to come by any research that shows that higher IQ leads to worse outcome (which your delta hypothesis claims).

We also know that iq correlated over 0.95 between same person taking the test on a different day, so any claim around daily fluctuation is exaggerated except for outlier cases. Your claims paint a different picture.

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Critical race theory explains IQ differences between socioeconomic groups (including races) extremely well.

Does it? Most of what I’ve seen amounts to assume races are have equal inherent IQ distributions, given test results are unequal the assumption is then tests must be inherently biased (examples of recent immigrant non-English speaking Jews improving their IQ scores as they learned English) or differences are caused by socio economic factors. That logic would fall apart if the original assumption wasn’t made, but anything starting with a prior that races can have different IQ distributions is thrown out as racist. The progressive book ‘The Genetic Lottery’ kind-of makes the case for polygenic factors considered evenly distributed amongst the races as a basis for that assumption but in my view their logic has a number of holes in it. If there is a better treatment of the topic I’m genuinely interested in reading it.

Nit: CRT certainly offers an explanation, but I don't think it's a particularly good one. Because it always appeals to "systemic injustice", it can't account for things like

1. the persistence of between group IQ differences amongst children people who have relocated to other countries/culture;

2. the disproportionate success of certain historically-marginalized groups;

3. regression to the mean; and,

4. other factors that marginally influence IQ scores (e.g. single-parent household vs dual-parent household)

without engaging in circular reasoning.

At best, CRT's explanation is incomplete.

Critical Race Theory is politically incorrect, under any definition of political correctness I know

Or people just haven't tried hard enough to find a politically correct explaination.

I think slavery itself could be one cause of it. Restricting the freedom to pick a partner of one group compared with other nearby groups seems likely to have an effect.

IQ is a mediocre-at-best metric for intelligence. "Intelligence" is probably real and variable among people, but poorly defined, very hard to test, and subject to a whole lot of opinion.

IQ is bad at comparing people from different backgrounds, especially across cultures, languages, etc.

But IQ can be a valid comparison for a single non-cultural variable. i.e. lead exposure in otherwise identical cohorts.

> otherwise identical cohorts.

You could do this stratification/matching for any IQ study. What's special about lead-IQ?

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I honestly don’t know enough about the theories to dismiss or validate them offhand, but the article quotes an official as saying that it seems as though the primary issue is that things like ceramic cookware and other household items had more lead in them than initially believed:

> Fuller said part of this "missing piece of the puzzle" was revealed in a Pure Earth report released on Tuesday, which analyzed 5,000 samples of consumer goods and food in 25 developing countries.

>It found high rates of lead contamination in metal pots and pans, ceramic cookware, paint, cosmetics and toys.

>"This is why poorer countries have so much lead poisoning," Fuller said. "It's items in the kitchen that are poisoning them."

Jet fuel never contained lead. (re: "chemtrails")

Old small piston-engined aircraft are now in the processes of validating and phasing out leaded fuel.

The primary sources of lead people consume will be from industrial pollution, old paint, and old water pipes.