8 ms·

The fatal attraction of lead

143 points by Libertatea 12y ago

4ad 12y ago
In Romania they used to still use lead plumbing until the early 2000s! As a kid, I loved that stuff, so maleable, you could do so many things from it, and it melted so easily. I loved to melt it and cast into into various shapes.
- johnward 12y ago
  I remember chewing on some lead fishing sinkers once or twice before my dad told me I was an idiot and playing with mercury one time when I broke a thermometer. I just wonder what "safe" things we use daily that we'll look back and say wtf were we thinking?
  - ianlevesque 12y ago
    Flame retardant furniture and children's clothing is a likely candidate.
- Spooky23 12y ago
  Lead pipes are very common in american cities for connecting residential service lines to water mains. Lead flux was also commonly used to seal drain pipes.
  - mikeash 12y ago
    I'd thought that lead water pipes were safe due to mineral buildup that shields them, but apparently this is not universally the case. Quoth Wikipedia: "Unlike other parts of the world where lead pipes cause poisoning, the Roman water had so much calcium in it, that a layer of plaque prevented the water contacting the lead itself."
    - shawabawa3 12y ago
      The article mentions that it's safe (relatively?) with hard water, but not with soft water
dctoedt 12y ago
I wonder if leaded gasoline is playing any kind of role in the continued unrest in the Middle East? FTA: Chronic lead exposure causes depression, headaches, aggression and memory loss. .... [M]any academics now believe leaded petrol was responsible for a global crime wave that peaked in the 1990s. ... Amazingly, a handful of countries - Iraq, Yemen, Burma, North Korea - continue to use leaded petrol.
- simonveal 12y ago
  This reminds me of a similar theory put forward by Edward de Bono a while back. He suggested it might be lack of zinc in the diet, caused by eating unleavened bread. He proposed shipping out Marmite to help. http://www.independent.co.uk/news/de-bonos-marmite-plan-for-peace-in-middle-yeast-1133338.html http://www.independent.co.uk/news/de-bonos-marmite-plan-for-...
- idlewords 12y ago
  "Unrest in the Middle East" is a blanket phrase so broad as to be meaningless. What specific conflict do you have in mind? Keep in mind that the number of vehicles per capita is much lower in Iraq and Yemen (the only two countries you mention) than in the United States. Your comment rubs me the wrong way since it speaks to a mindset where complicated geopolitical problems can be solved or explained by a simple hack. Don't use lead! Peace treaties to follow.
  - mikeash 12y ago
    If it were truly a simple hack, it would already be done, since the health benefits are well known. Getting these countries to stop burning leaded gasoline sounds like a fairly hard problem to me, just from the fact that they keep doing it. A sibling poster mentions how many problems have had simple solutions, like vitamin C for scurvy, which is true in the abstract but they all took quite a lot of fighting to implement. Now, I doubt that lead is a significant factor here. But even if it were and it could be demonstrated, would it really be "simple"?
  - dctoedt 12y ago
    > What specific [Middle East] conflict do you have in mind? There are so many .... > Keep in mind that the number of vehicles per capita is much lower in Iraq and Yemen Certainly that's a datum to take into account (I'm not being sarcastic). > Your comment ... speaks to a mindset where complicated geopolitical problems can be solved or explained by a simple hack. Does it now?
tobinfricke 12y ago
Surprisingly, the fuel used in piston-powered aircraft generally still contains lead: http://en.wikipedia.org/wiki/Avgas http://en.wikipedia.org/wiki/Avgas Wikipedia says that the amount of lead in 100LL avgas is "about 4 times what was in pre-1975 leaded automotive grade gasoline." As a private pilot, yes I do feel a bit guilty that my hobby adds lead to the environment ...
- SpacemanSpiff 12y ago
  Thankfully, the general aviation industry in the US is moving away from leaded avgas. http://www.aopa.org/News-and-Video/All-News/2014/September/08/FAA-selects-four-unleaded-fuels-for-testing http://www.aopa.org/News-and-Video/All-News/2014/September/0...
  - tobinfricke 12y ago
    Unfortunately (and I say this as a member of the organization), I feel like the AOPA is fighting - or at least dragging its feet - on the issue, since transition to any other fuel is likely to add some kind of expense or inconvenience.
- gsnedders 12y ago
  A large proportion of piston-powered aircraft are relatively old — many are general aviation aircraft, and the hours put on the airframes are small compared with most commercial aircraft, so most predate the ban of leaded automotive fuel. There's a lot of resistance to changing anything around aviation, especially when it comes to engines. Many (or most?) piston-powered aircraft are single-engined aircraft, where a single failure makes the plane a glider.
  - dghughes 12y ago
    Old being the key since the engines require lead for valve lubrication and most have a carburetor not fuel-injection so power is not as good as fuel-injected. Getting power out of a certain quantity of fuel is also a big plus since the 100 liters of leaded avgas you carry can take you 600km but unleaded maybe only 500km.
lysium 12y ago
I'm still impressed by the seemingly high correlation between gasoline lead exposure and violent crimes.
- piquadrat 12y ago
  Mother Jones had a very interesting story about the topic a while ago: http://www.motherjones.com/environment/2013/01/lead-crime-link-gasoline http://www.motherjones.com/environment/2013/01/lead-crime-li...
comrade1 12y ago
And it tastes so so sweet... When my friends and I were children we found pieces of lead while dumpster diving. Probably 5 pounds of it. We taught ourselves how to make plaster-of-paris molds and tried to counterfeit the most important thing to us - video game tokens from the local arcade. We made only a handful of tokens before we realized the effort was more than the payoff. We had to rebuild the mold each time and break it with a hammer to pull out the token. We never even tried the tokens. And I think the lead fumes from melting it on a bunsen burner from my Christmas chemistry set probably didn't help us in the long run... Making nitrogen tri-iodide in high-school had a much better payoff, even if we had to steal the solid iodine from the chemistry class supply closet. This was before the internet and so we learned this one from the anarchist's cookbook. My cat hated walking in the basement after each batch. Did anyone else experience the purple acrid smoke at the back of your throat?
- myself248 12y ago
  > And it tastes so so sweet... You mean wall candy? http://www.penny-arcade.com/comic/1999/10/18 http://www.penny-arcade.com/comic/1999/10/18
- danieltillett 12y ago
  I did the same thing as as a kid with my brother (we broken open batteries instead to get the lead). I never tried to spend the “money” we made, but just used it to impress other kids in the playground. I guess this is where some of the appeal of physical gold comes from - the weight of these coins when held in the hand sure impressed. We avoided breaking the mould by casting the plaster of paris in two sections. The first you cast to halfway up the side of the coin lying flat and once it sets you rub grease over the top of everything and then cast the over half. Once everything has dried the two half split apart easy. We put in little sticks into the first cast sticking up 5mm so that the two halves could be aligned again after removing the coin. You could use this mould as many times as you liked. I do agree that the effort far out weighed the financial reward though :) Someone should start making and selling gold plated tungsten coins as a cheap replica of gold coins - I know this sometimes happens as forgeries, but it would be nice to have a few hundred of these to play around with and impress your friends. Edit. It looks like there is a company in China that actually does this. I have contacted them to see what they cost as I would love to have some of these.
kirsebaer 12y ago
Lead paint and lead gasoline are shocking examples of corporate misbehavior. Interior lead paint was banned in many European countries by the 1920s because of the obvious health risks. But in the US the lead manufactures responded to health concerns with "Dutch Boy" lead paint, deliberately marketed to appear safe enough for a child to use. They actually had advertising campaigns promoting lead paint for childrens' toys, cribs, and bedrooms. Household lead paint not banned in the US until 1978, and it now a major concern and cost for people living in older homes. The health risks of leaded gasoline were also obvious to many, and ethanol was known as a safe alternative anti-knock additive in the 1920s. General Motors and Alfred P. Sloan tried to hide the risks of lead paint via front groups and manipulation of regulatory agencies. http://www.youtube.com/watch?v=TLoixnECec0 http://www.youtube.com/watch?v=TLoixnECec0 Video about Dutch Boy paint advertising to children. http://www.theatlantic.com/health/archive/2013/04/why-it-took-decades-of-blaming-parents-before-we-banned-lead-paint/275169/ http://www.theatlantic.com/health/archive/2013/04/why-it-too... David Rosner is the Ronald H. Lauterstein Professor of Sociomedical Sciences and a professor of history at Columbia University. Gerald Markowitz is a Distinguished Professor of History at John Jay College and CUNY Graduate Center. Their most recent book is Lead Wars: The Politics of Science and the Fate of Americaís Children. http://www.theguardian.com/commentisfree/2013/jan/07/violent-crime-lead-poisoning-british-export http://www.theguardian.com/commentisfree/2013/jan/07/violent... Yes, lead poisoning could really be a cause of violent crime, by George Monbiot http://www.huffingtonpost.com/2013/08/03/lead-paint-lawsuit-california-tobacco-industry_n_3696533.html http://www.huffingtonpost.com/2013/08/03/lead-paint-lawsuit-... Lead Paint Makers Could Face The Same Fate As Big Tobacco http://www.thenation.com/article/secret-history-lead http://www.thenation.com/article/secret-history-lead The Secret History of Lead
- _delirium 12y ago
  Interesting, I hadn't realized the first bans were as early as the 1920s. Researching a bit now, it seems like concerns were raised by at least the 19th century, and were pretty solid by the early 20th, which is not at all how I've heard it presented previously. I had previously assumed that it was not really known to science until the 1960s or so, which seems untrue. From what I've found in some quick digging, it seems like the early bans were driven by workplace-safety concerns (rather than residential safety), as unions agitated to ban dangerous substances that had been causing health problems for painters and other workers who were exposed to it (e.g. through sanding). There was a 1921 convention of the International Labor Organization to that effect, but the U.S. didn't sign: https://en.wikipedia.org/wiki/White_Lead_%28Painting%29_Convention,_1921 https://en.wikipedia.org/wiki/White_Lead_%28Painting%29_Conv...
RankingMember 12y ago
Various causes have been credited for the decline of violent crime in the 1990s in the U.S., one of which was the legalization of abortion in 1973. I didn't realize violent crime declined globally at the same time. That makes me think that perhaps leaded gas is a more likely culprit. Untreated ADHD has also been linked to violent crime, so with any luck we'll continue the downward trend in violent incidence as the treatment of ADHD continues. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3398051/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3398051/
notastartup 12y ago
The crime rate correlation with lead tainted gasoline is fascinating. Could it be that in lower socioeconomic areas have older cars that produces lead in to the air, and the population ends up breathing a lot of it?
- mikeash 12y ago
  Lead emissions come from the gasoline that's burned, not the cars burning it. Once leaded gasoline was eliminated, lead emissions from cars ceased.
  - j1o1h1n 12y ago
    New cars are required to be fitted with catalytic converters that reduce pollutants.
    - mikeash 12y ago
      Those help burn stuff like hydrocarbons and carbon monoxide in the exhaust. It's unrelated to lead.
      - invaliddata 12y ago
        Not entirely unrelated. Exhaust catalysts are easily "poisoned," by lead among other things. Leaded gasoline would do it, so modern catalysts would never have been fitted to cars permitted to run leaded gasoline (very relevant during the time when both leaded and unleaded were available). Or put another way, the "unleaded only" signs you see on some older cars was not because the cars wouldn't run, but because running leaded gasoline would quickly degrade the emissions control equipment (oxygen sensors and catalysts primarily)
- mturmon 12y ago
  You have been downvoted, but you have a point. In the 1970s, you could buy both leaded and unleaded gas at service stations. New cars used unleaded gas, but old ones "required" leaded for various reasons that turned out to be mostly wrong (http://www.stevelinden.com/unleaded-gas-vs-regular-gas-in-classic-cars http://www.stevelinden.com/unleaded-gas-vs-regular-gas-in-cl...). Unleaded was required to work with the catalytic converters that were newly required in cars. Regular leaded gas was cheaper. My neighbor had the catalytic converter in his car removed (it was illegal) so he could use the cheaper leaded gas. So there would be an effect in which old cars imply more lead.
cmatteri 12y ago
The use of leaded paint indoors and of leaded gasoline were particularly dangerous, but there are still numerous potential sources of lead exposure, especially in certain industries, but also for the average person. Exposure has decreased, but the safe blood lead level has also been reduced as we become increasingly aware of the harms of sub-clinical lead poisoning. Two interesting properties of lead's toxicity that weren't mentioned in the article are its potency and its ability to accumulate. A blood lead level of 10 ug/dL is often listed as a threshold for concern (though for children 5 ug/dL or less is more appropriate). A typical blood volume for an adult is around 50 dL (according to Wikipedia), so 10 ug/dL would mean that there are 500 ug of lead in your blood. Lead has a density of 11.3 g/cm^3, so 500 ug has a volume of 44.2 nL. If you have every used a 2 uL pipette, you would have an idea of how small of a volume 44.2 nL is (for those who haven't, it's somewhere in the range of a grain of sand http://en.wikipedia.org/wiki/Orders_of_magnitude_%28volume%29 http://en.wikipedia.org/wiki/Orders_of_magnitude_%28volume%2...). Although not all the lead we ingest is absorbed and lead is distributed throughout various organs, this should give a sense of how potent of a toxin lead is. Lead is also cleared from the body fairly slowly, so the amount of exposure per day needed to build up to a toxic level is even lower. These two properties, combined with the ubiquity of lead in our society, the long timescales over which it causes harm, and widespread ignorance of or apathy towards its harms are why I find it a particularly frightening toxin. One source that could be relevant to some in the HN crowd is electronics solder. Although Europe banned the use of lead in electronic components and solder in most applications in 2006 with RoHS, leaded solder is still mostly legal and common in the US (it looks like CA has partially adopted RoHS http://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive#North_America http://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substa...). It is fairly easy to use leaded hand solder safely, but it is also entirely plausible that a child with inadequate training or supervision could ingest a significant amount of lead while soldering, from the small flakes of solder that accumulate on your workbench, dust, or lead oxides on a sponge. I had no idea how toxic lead was when I taught myself to solder in high school, and I'm glad I didn't do it much then for that reason. I have recently started using Sn96.5Ag3Cu0.5 (lead free) solder, and although it is somewhat more expensive that leaded solder, with proper tools, plated PCBs, and correct technique it is really quite easy to use. I have some aggressive rosin-activated flux on hand (that requires cleanup) but I haven't needed to use it so far. I would highly recommend trying out Sn96.5Ag3Cu0.5, especially if you're sharing a workspace with children, who are far more susceptible to lead for various reasons. A fair number of materials that you might encounter can contain lead as an additive, including plastic, brass, bronze, steel (http://en.wikipedia.org/wiki/Free_machining_steel http://en.wikipedia.org/wiki/Free_machining_steel), and metal/hobby/industrial/artist paints. It's always worth looking up what hazardous compounds may be present in something before putting a grinder to it (again, something I hadn't mastered in high school). More along the lines of the article, here is another particularly egregious historical use of lead as a color in candy. In this case the compound, lead (II) chromate, also contained hexavalent chromium, another particularly hazardous chemical (http://books.google.co.uk/books?id=aC9NAAAAMAAJ&pg=PA93&dq=%22chromate+of+lead%22+candy http://books.google.co.uk/books?id=aC9NAAAAMAAJ&pg=PA93&dq=%...).
GhotiFish 12y ago
You know, we really ought to rename Tantalum->Lead, and Lead->Tantalum. Can someone clarify what the last part of the article was saying? In some hotspots - downwind from old smelters, or where miners dumped their spoils - it can be as high as 3%. Does that seriously mean you could scoop a handful of dirt and 3% of that would be lead?!
- masklinn 12y ago
  Yes, though I expect it's 3% by mass, so for 1kg of soil you get 30g of lead (30000ppm). For reference, uncontaminated natural soil averages 10ppm.
- dredmorbius 12y ago
  Given that that's probably percentage by weight, and the density of lead itself, possibly.
frik 12y ago
The european union (EU) banned lead gasoline in 2000 (~ 2005 "lead free"), USA already in 1978. Many airplanes can still legally use lead fuel. source (german): http://de.wikipedia.org/wiki/Motorenbenzin#Verbleites_Benzin http://de.wikipedia.org/wiki/Motorenbenzin#Verbleites_Benzin
- masklinn 12y ago
  > The european union (EU) banned lead gasoline in 2000 (~ 2005 "lead free"), USA already in 1978. These dates are to completely different events. The US started phasing out leaded gas in the mid-70s (the EPA announced its first regs in 1975, effective 1978) but didn't complete the phaseout until 1996. The EU did start and complete its phaseout later (starting in 1981, in part because of the resistance of some members e.g. France) but a few member states did so much earlier (Germany started phasing out leaded in 1972 and had completed its phaseout by 1988).
  - frik 12y ago
    In Austria gas stations offered lead gasoline til 1993: http://sciencev1.orf.at/science/news/67046 http://sciencev1.orf.at/science/news/67046
  - blisterpeanuts 12y ago
    Wikipedia[1] lists the U.S. phaseout as having completed in 1995. Some of the countries mentioned in the BBC article are phasing out leaded gasoline: Algeria in 2014, Iraq in 2015. I wonder why it's still even called "unleaded" in the U.S. when you can't even buy leaded gasoline anymore. Maybe it should just be called gasoline or better yet, petrol. The commonly used term "gas" is confusing because Americans use it to refer to liquid refined petroleum fuel i.e. gasoline, yet also to refer to gaseous substances that include methane and other fossil fuels. 1. http://en.wikipedia.org/wiki/Tetraethyllead http://en.wikipedia.org/wiki/Tetraethyllead
ern 12y ago
As nasty as lead is, a few things make me wonder if some of the claims, particularly regarding low levels of lead and IQ, are on shaky ground. The Flynn Effect continued despite lead levels rising during the twentieth century. Now that lead has been eliminated, there should be clear increases in IQ- have these been found?
DonHopkins 12y ago
My grandparents had lead christmas tree tinsel, which they carefully removed from the tree at the end of christmas and packed away for next year. It was admittedly beautiful, and it hung straight down without fluttering around like that cheap plastic stuff!
gadders 12y ago
For those that liked the article, it's basically a re-write of one of the episodes of the Elements podcast from the BBC World Service. You can get the other episodes here: http://www.bbc.co.uk/podcasts/series/elements http://www.bbc.co.uk/podcasts/series/elements It's very entertaining and highly recommended.

143 points by Libertatea 12y ago

4ad 12y ago

In Romania they used to still use lead plumbing until the early 2000s! As a kid, I loved that stuff, so maleable, you could do so many things from it, and it melted so easily. I loved to melt it and cast into into various shapes.

johnward 12y ago
I remember chewing on some lead fishing sinkers once or twice before my dad told me I was an idiot and playing with mercury one time when I broke a thermometer. I just wonder what "safe" things we use daily that we'll look back and say wtf were we thinking?
- ianlevesque 12y ago
  Flame retardant furniture and children's clothing is a likely candidate.
Spooky23 12y ago
Lead pipes are very common in american cities for connecting residential service lines to water mains. Lead flux was also commonly used to seal drain pipes.
- mikeash 12y ago
  I'd thought that lead water pipes were safe due to mineral buildup that shields them, but apparently this is not universally the case. Quoth Wikipedia: "Unlike other parts of the world where lead pipes cause poisoning, the Roman water had so much calcium in it, that a layer of plaque prevented the water contacting the lead itself."
  - shawabawa3 12y ago
    The article mentions that it's safe (relatively?) with hard water, but not with soft water

dctoedt 12y ago

I wonder if leaded gasoline is playing any kind of role in the continued unrest in the Middle East? FTA: Chronic lead exposure causes depression, headaches, aggression and memory loss. .... [M]any academics now believe leaded petrol was responsible for a global crime wave that peaked in the 1990s. ... Amazingly, a handful of countries - Iraq, Yemen, Burma, North Korea - continue to use leaded petrol.

simonveal 12y ago
This reminds me of a similar theory put forward by Edward de Bono a while back. He suggested it might be lack of zinc in the diet, caused by eating unleavened bread. He proposed shipping out Marmite to help. http://www.independent.co.uk/news/de-bonos-marmite-plan-for-peace-in-middle-yeast-1133338.html http://www.independent.co.uk/news/de-bonos-marmite-plan-for-...
idlewords 12y ago
"Unrest in the Middle East" is a blanket phrase so broad as to be meaningless. What specific conflict do you have in mind? Keep in mind that the number of vehicles per capita is much lower in Iraq and Yemen (the only two countries you mention) than in the United States. Your comment rubs me the wrong way since it speaks to a mindset where complicated geopolitical problems can be solved or explained by a simple hack. Don't use lead! Peace treaties to follow.
- mikeash 12y ago
  If it were truly a simple hack, it would already be done, since the health benefits are well known. Getting these countries to stop burning leaded gasoline sounds like a fairly hard problem to me, just from the fact that they keep doing it. A sibling poster mentions how many problems have had simple solutions, like vitamin C for scurvy, which is true in the abstract but they all took quite a lot of fighting to implement. Now, I doubt that lead is a significant factor here. But even if it were and it could be demonstrated, would it really be "simple"?
- dctoedt 12y ago
  > What specific [Middle East] conflict do you have in mind? There are so many .... > Keep in mind that the number of vehicles per capita is much lower in Iraq and Yemen Certainly that's a datum to take into account (I'm not being sarcastic). > Your comment ... speaks to a mindset where complicated geopolitical problems can be solved or explained by a simple hack. Does it now?

tobinfricke 12y ago

Surprisingly, the fuel used in piston-powered aircraft generally still contains lead: http://en.wikipedia.org/wiki/Avgas http://en.wikipedia.org/wiki/Avgas Wikipedia says that the amount of lead in 100LL avgas is "about 4 times what was in pre-1975 leaded automotive grade gasoline." As a private pilot, yes I do feel a bit guilty that my hobby adds lead to the environment ...

SpacemanSpiff 12y ago
Thankfully, the general aviation industry in the US is moving away from leaded avgas. http://www.aopa.org/News-and-Video/All-News/2014/September/08/FAA-selects-four-unleaded-fuels-for-testing http://www.aopa.org/News-and-Video/All-News/2014/September/0...
- tobinfricke 12y ago
  Unfortunately (and I say this as a member of the organization), I feel like the AOPA is fighting - or at least dragging its feet - on the issue, since transition to any other fuel is likely to add some kind of expense or inconvenience.
gsnedders 12y ago
A large proportion of piston-powered aircraft are relatively old — many are general aviation aircraft, and the hours put on the airframes are small compared with most commercial aircraft, so most predate the ban of leaded automotive fuel. There's a lot of resistance to changing anything around aviation, especially when it comes to engines. Many (or most?) piston-powered aircraft are single-engined aircraft, where a single failure makes the plane a glider.
- dghughes 12y ago
  Old being the key since the engines require lead for valve lubrication and most have a carburetor not fuel-injection so power is not as good as fuel-injected. Getting power out of a certain quantity of fuel is also a big plus since the 100 liters of leaded avgas you carry can take you 600km but unleaded maybe only 500km.

lysium 12y ago

I'm still impressed by the seemingly high correlation between gasoline lead exposure and violent crimes.

piquadrat 12y ago
Mother Jones had a very interesting story about the topic a while ago: http://www.motherjones.com/environment/2013/01/lead-crime-link-gasoline http://www.motherjones.com/environment/2013/01/lead-crime-li...

comrade1 12y ago

And it tastes so so sweet... When my friends and I were children we found pieces of lead while dumpster diving. Probably 5 pounds of it. We taught ourselves how to make plaster-of-paris molds and tried to counterfeit the most important thing to us - video game tokens from the local arcade. We made only a handful of tokens before we realized the effort was more than the payoff. We had to rebuild the mold each time and break it with a hammer to pull out the token. We never even tried the tokens. And I think the lead fumes from melting it on a bunsen burner from my Christmas chemistry set probably didn't help us in the long run... Making nitrogen tri-iodide in high-school had a much better payoff, even if we had to steal the solid iodine from the chemistry class supply closet. This was before the internet and so we learned this one from the anarchist's cookbook. My cat hated walking in the basement after each batch. Did anyone else experience the purple acrid smoke at the back of your throat?

myself248 12y ago
> And it tastes so so sweet... You mean wall candy? http://www.penny-arcade.com/comic/1999/10/18 http://www.penny-arcade.com/comic/1999/10/18
danieltillett 12y ago
I did the same thing as as a kid with my brother (we broken open batteries instead to get the lead). I never tried to spend the “money” we made, but just used it to impress other kids in the playground. I guess this is where some of the appeal of physical gold comes from - the weight of these coins when held in the hand sure impressed. We avoided breaking the mould by casting the plaster of paris in two sections. The first you cast to halfway up the side of the coin lying flat and once it sets you rub grease over the top of everything and then cast the over half. Once everything has dried the two half split apart easy. We put in little sticks into the first cast sticking up 5mm so that the two halves could be aligned again after removing the coin. You could use this mould as many times as you liked. I do agree that the effort far out weighed the financial reward though :) Someone should start making and selling gold plated tungsten coins as a cheap replica of gold coins - I know this sometimes happens as forgeries, but it would be nice to have a few hundred of these to play around with and impress your friends. Edit. It looks like there is a company in China that actually does this. I have contacted them to see what they cost as I would love to have some of these.

kirsebaer 12y ago

Lead paint and lead gasoline are shocking examples of corporate misbehavior. Interior lead paint was banned in many European countries by the 1920s because of the obvious health risks. But in the US the lead manufactures responded to health concerns with "Dutch Boy" lead paint, deliberately marketed to appear safe enough for a child to use. They actually had advertising campaigns promoting lead paint for childrens' toys, cribs, and bedrooms. Household lead paint not banned in the US until 1978, and it now a major concern and cost for people living in older homes. The health risks of leaded gasoline were also obvious to many, and ethanol was known as a safe alternative anti-knock additive in the 1920s. General Motors and Alfred P. Sloan tried to hide the risks of lead paint via front groups and manipulation of regulatory agencies. http://www.youtube.com/watch?v=TLoixnECec0 http://www.youtube.com/watch?v=TLoixnECec0 Video about Dutch Boy paint advertising to children. http://www.theatlantic.com/health/archive/2013/04/why-it-took-decades-of-blaming-parents-before-we-banned-lead-paint/275169/ http://www.theatlantic.com/health/archive/2013/04/why-it-too... David Rosner is the Ronald H. Lauterstein Professor of Sociomedical Sciences and a professor of history at Columbia University. Gerald Markowitz is a Distinguished Professor of History at John Jay College and CUNY Graduate Center. Their most recent book is Lead Wars: The Politics of Science and the Fate of Americaís Children. http://www.theguardian.com/commentisfree/2013/jan/07/violent-crime-lead-poisoning-british-export http://www.theguardian.com/commentisfree/2013/jan/07/violent... Yes, lead poisoning could really be a cause of violent crime, by George Monbiot http://www.huffingtonpost.com/2013/08/03/lead-paint-lawsuit-california-tobacco-industry_n_3696533.html http://www.huffingtonpost.com/2013/08/03/lead-paint-lawsuit-... Lead Paint Makers Could Face The Same Fate As Big Tobacco http://www.thenation.com/article/secret-history-lead http://www.thenation.com/article/secret-history-lead The Secret History of Lead

_delirium 12y ago
Interesting, I hadn't realized the first bans were as early as the 1920s. Researching a bit now, it seems like concerns were raised by at least the 19th century, and were pretty solid by the early 20th, which is not at all how I've heard it presented previously. I had previously assumed that it was not really known to science until the 1960s or so, which seems untrue. From what I've found in some quick digging, it seems like the early bans were driven by workplace-safety concerns (rather than residential safety), as unions agitated to ban dangerous substances that had been causing health problems for painters and other workers who were exposed to it (e.g. through sanding). There was a 1921 convention of the International Labor Organization to that effect, but the U.S. didn't sign: https://en.wikipedia.org/wiki/White_Lead_%28Painting%29_Convention,_1921 https://en.wikipedia.org/wiki/White_Lead_%28Painting%29_Conv...

RankingMember 12y ago

Various causes have been credited for the decline of violent crime in the 1990s in the U.S., one of which was the legalization of abortion in 1973. I didn't realize violent crime declined globally at the same time. That makes me think that perhaps leaded gas is a more likely culprit. Untreated ADHD has also been linked to violent crime, so with any luck we'll continue the downward trend in violent incidence as the treatment of ADHD continues. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3398051/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3398051/

notastartup 12y ago

The crime rate correlation with lead tainted gasoline is fascinating. Could it be that in lower socioeconomic areas have older cars that produces lead in to the air, and the population ends up breathing a lot of it?

mikeash 12y ago
Lead emissions come from the gasoline that's burned, not the cars burning it. Once leaded gasoline was eliminated, lead emissions from cars ceased.
- j1o1h1n 12y ago
  New cars are required to be fitted with catalytic converters that reduce pollutants.
  - mikeash 12y ago
    Those help burn stuff like hydrocarbons and carbon monoxide in the exhaust. It's unrelated to lead.
    - invaliddata 12y ago
      Not entirely unrelated. Exhaust catalysts are easily "poisoned," by lead among other things. Leaded gasoline would do it, so modern catalysts would never have been fitted to cars permitted to run leaded gasoline (very relevant during the time when both leaded and unleaded were available). Or put another way, the "unleaded only" signs you see on some older cars was not because the cars wouldn't run, but because running leaded gasoline would quickly degrade the emissions control equipment (oxygen sensors and catalysts primarily)
mturmon 12y ago
You have been downvoted, but you have a point. In the 1970s, you could buy both leaded and unleaded gas at service stations. New cars used unleaded gas, but old ones "required" leaded for various reasons that turned out to be mostly wrong (http://www.stevelinden.com/unleaded-gas-vs-regular-gas-in-classic-cars http://www.stevelinden.com/unleaded-gas-vs-regular-gas-in-cl...). Unleaded was required to work with the catalytic converters that were newly required in cars. Regular leaded gas was cheaper. My neighbor had the catalytic converter in his car removed (it was illegal) so he could use the cheaper leaded gas. So there would be an effect in which old cars imply more lead.

cmatteri 12y ago

The use of leaded paint indoors and of leaded gasoline were particularly dangerous, but there are still numerous potential sources of lead exposure, especially in certain industries, but also for the average person. Exposure has decreased, but the safe blood lead level has also been reduced as we become increasingly aware of the harms of sub-clinical lead poisoning. Two interesting properties of lead's toxicity that weren't mentioned in the article are its potency and its ability to accumulate. A blood lead level of 10 ug/dL is often listed as a threshold for concern (though for children 5 ug/dL or less is more appropriate). A typical blood volume for an adult is around 50 dL (according to Wikipedia), so 10 ug/dL would mean that there are 500 ug of lead in your blood. Lead has a density of 11.3 g/cm^3, so 500 ug has a volume of 44.2 nL. If you have every used a 2 uL pipette, you would have an idea of how small of a volume 44.2 nL is (for those who haven't, it's somewhere in the range of a grain of sand http://en.wikipedia.org/wiki/Orders_of_magnitude_%28volume%29 http://en.wikipedia.org/wiki/Orders_of_magnitude_%28volume%2...). Although not all the lead we ingest is absorbed and lead is distributed throughout various organs, this should give a sense of how potent of a toxin lead is. Lead is also cleared from the body fairly slowly, so the amount of exposure per day needed to build up to a toxic level is even lower. These two properties, combined with the ubiquity of lead in our society, the long timescales over which it causes harm, and widespread ignorance of or apathy towards its harms are why I find it a particularly frightening toxin. One source that could be relevant to some in the HN crowd is electronics solder. Although Europe banned the use of lead in electronic components and solder in most applications in 2006 with RoHS, leaded solder is still mostly legal and common in the US (it looks like CA has partially adopted RoHS http://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive#North_America http://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substa...). It is fairly easy to use leaded hand solder safely, but it is also entirely plausible that a child with inadequate training or supervision could ingest a significant amount of lead while soldering, from the small flakes of solder that accumulate on your workbench, dust, or lead oxides on a sponge. I had no idea how toxic lead was when I taught myself to solder in high school, and I'm glad I didn't do it much then for that reason. I have recently started using Sn96.5Ag3Cu0.5 (lead free) solder, and although it is somewhat more expensive that leaded solder, with proper tools, plated PCBs, and correct technique it is really quite easy to use. I have some aggressive rosin-activated flux on hand (that requires cleanup) but I haven't needed to use it so far. I would highly recommend trying out Sn96.5Ag3Cu0.5, especially if you're sharing a workspace with children, who are far more susceptible to lead for various reasons. A fair number of materials that you might encounter can contain lead as an additive, including plastic, brass, bronze, steel (http://en.wikipedia.org/wiki/Free_machining_steel http://en.wikipedia.org/wiki/Free_machining_steel), and metal/hobby/industrial/artist paints. It's always worth looking up what hazardous compounds may be present in something before putting a grinder to it (again, something I hadn't mastered in high school). More along the lines of the article, here is another particularly egregious historical use of lead as a color in candy. In this case the compound, lead (II) chromate, also contained hexavalent chromium, another particularly hazardous chemical (http://books.google.co.uk/books?id=aC9NAAAAMAAJ&pg=PA93&dq=%22chromate+of+lead%22+candy http://books.google.co.uk/books?id=aC9NAAAAMAAJ&pg=PA93&dq=%...).

GhotiFish 12y ago

You know, we really ought to rename Tantalum->Lead, and Lead->Tantalum. Can someone clarify what the last part of the article was saying? In some hotspots - downwind from old smelters, or where miners dumped their spoils - it can be as high as 3%. Does that seriously mean you could scoop a handful of dirt and 3% of that would be lead?!

masklinn 12y ago
Yes, though I expect it's 3% by mass, so for 1kg of soil you get 30g of lead (30000ppm). For reference, uncontaminated natural soil averages 10ppm.
dredmorbius 12y ago
Given that that's probably percentage by weight, and the density of lead itself, possibly.

frik 12y ago

The european union (EU) banned lead gasoline in 2000 (~ 2005 "lead free"), USA already in 1978. Many airplanes can still legally use lead fuel. source (german): http://de.wikipedia.org/wiki/Motorenbenzin#Verbleites_Benzin http://de.wikipedia.org/wiki/Motorenbenzin#Verbleites_Benzin

masklinn 12y ago
> The european union (EU) banned lead gasoline in 2000 (~ 2005 "lead free"), USA already in 1978. These dates are to completely different events. The US started phasing out leaded gas in the mid-70s (the EPA announced its first regs in 1975, effective 1978) but didn't complete the phaseout until 1996. The EU did start and complete its phaseout later (starting in 1981, in part because of the resistance of some members e.g. France) but a few member states did so much earlier (Germany started phasing out leaded in 1972 and had completed its phaseout by 1988).
- frik 12y ago
  In Austria gas stations offered lead gasoline til 1993: http://sciencev1.orf.at/science/news/67046 http://sciencev1.orf.at/science/news/67046
- blisterpeanuts 12y ago
  Wikipedia[1] lists the U.S. phaseout as having completed in 1995. Some of the countries mentioned in the BBC article are phasing out leaded gasoline: Algeria in 2014, Iraq in 2015. I wonder why it's still even called "unleaded" in the U.S. when you can't even buy leaded gasoline anymore. Maybe it should just be called gasoline or better yet, petrol. The commonly used term "gas" is confusing because Americans use it to refer to liquid refined petroleum fuel i.e. gasoline, yet also to refer to gaseous substances that include methane and other fossil fuels. 1. http://en.wikipedia.org/wiki/Tetraethyllead http://en.wikipedia.org/wiki/Tetraethyllead

ern 12y ago

As nasty as lead is, a few things make me wonder if some of the claims, particularly regarding low levels of lead and IQ, are on shaky ground. The Flynn Effect continued despite lead levels rising during the twentieth century. Now that lead has been eliminated, there should be clear increases in IQ- have these been found?

DonHopkins 12y ago

My grandparents had lead christmas tree tinsel, which they carefully removed from the tree at the end of christmas and packed away for next year. It was admittedly beautiful, and it hung straight down without fluttering around like that cheap plastic stuff!

gadders 12y ago

For those that liked the article, it's basically a re-write of one of the episodes of the Elements podcast from the BBC World Service. You can get the other episodes here: http://www.bbc.co.uk/podcasts/series/elements http://www.bbc.co.uk/podcasts/series/elements It's very entertaining and highly recommended.