16 ms·

A Study That Bolsters the Lead-Crime Hypothesis

210 points by curtis 9y ago

rntz 9y ago
The article title on the original site was changed from "... Confirms the Lead-Crime Hypothesis" to "... Bolsters the Lead-Crime Hypothesis", since "It's a good study, but it's still just one more study." Title here should be changed likewise.
- sctb 9y ago
  Thank you, we've updated the headline here.
douche 9y ago
The lead-violence correlation is very, very interesting. What always makes me wonder is how much historical effect environmental factors like this must have had. Lead used to be ubiquitous, between paint, pipes, roofing, glass, solder - the Romans even cooked in lead vessels at times. There's probably no way of ever teasing out all the different factors, but when you read accounts of what daily life was like in, say 18th century London, and a.) violence was quite common-place, and b.) virtually everyone kept themselves inebriated enough to fail a breathalyzer at all times. Probably b.) contributed a good deal to a.), but if everybody is also suffering from low-level chronic lead poisoning...
- snovv_crash 9y ago
  Never mind cooking in lead vessels, they used lead acetate as an artificial sweetener in their food. I've often wondered if this was something that contributed to their downfall.
  - wil421 9y ago
    I'm sure it didn't help Caligula. It seems a lot of crazy acting emperors could be linked to lead poisoning. It makes me think what people 50-100 years will think about our diets. They put sugar in everything!
    - tcoppi 9y ago
      More likely to be the huge amount of plasticizers that have been making their way into our diet, imo.
    - AnimalMuppet 9y ago
      You know, it would explain a lot of things if, over the last 10 or 20 years, something were slowly driving more and more people crazy...
      - posterboy 9y ago
        The Opium epidemic lead to a freaking trade war [1]. How about crack cocaine and other designer drugs, incl. highly potent cannabis, alcohol and cigarettes as factors? [1]: https://en.wikipedia.org/wiki/Opium_Wars https://en.wikipedia.org/wiki/Opium_Wars
  - Tharkun 9y ago
    What makes it worse is that the Romans knew lead was toxic. But they thought its effect was limited to the production process, which was mostly done by slaves and other people of no apparent value.
- naasking 9y ago
  Crime and violence has been falling steadily over the past century too. Makes you wonder if this significant social change isn't because of better education, social programs, etc., but simply because of other factors like this that we're simply unaware of.
  - ceejayoz 9y ago
    As pointed out elsewhere in the thread, different countries phased out tetraethyl lead in gasoline at different times, and their respective drops in crime correlate well with those dates.
  - Gibbon1 9y ago
    No one disputes that other factors are important. For instance cultural attitudes about violence are important. As is the reach of civil government. Not to mention that in the US violence is a particular problem because of ready access to handguns. My take having read about this theory for about ten years now it looks like the preponderance of the evidence says that lead exposure is at least as significant as the above. Meaning it's not just this study, it's all the other ones as well. With the lead thoery you have the following. 1. A known mechanism. Lead cause brain damage with poor impulse control. 2. Dose response correlation between lead exposure and violent crime. Thing that freaks me out is what did exposure to lead and resulting poor impulse control do to politics in the US.
  - bjourne 9y ago
    It hasn't. See this graph f.e https://ourworldindata.org/wp-content/uploads/2013/03/homicide-rates-in-the-united-states-1950-2010-and-canada-1961-2009-pinker-2011-jpg.jpg https://ourworldindata.org/wp-content/uploads/2013/03/homici... In many countries, violent crime exploded in the late 1960s and then increased until the mid 1990s after which it began decreasing again.
alexilliamson 9y ago
From the article: "The statistical significance of the drop is extremely strong" I haven't read the source paper yet, but the way this is phrased makes me skeptical of the strength of these findings. Having worked briefly on a lead remediation project for a city government who has been in the news recently for lead, I can tell you that this is a really tough question and the confounding factors are huge. The political consequences mean that folks have incentive to seriously overstate (or understate) the importance and validity of a study like this.
- anigbrowl 9y ago
  I really think you ought to read it before making such a dismissive comment.
- nabla9 9y ago
  There have been several studies over the years and the evidence is strong. Crime rates seem to drop with 20 year lag after TEL phaseout in gasoline starts. Different countries banned TEL at different times and it's very hard to deny connection.
- sloppycee 9y ago
  Unfortunate that you're being down-voted for being skeptical, this study does have some issues confounding the results: "The elevated BLL intervention package includes treatments previously demonstrated to impact later-life outcomes such as: visits from health workers; increased medical care; nutritional assessments and dietary modifications; and referral to the Special Supplemental, Nutrition Program for Women, Infants, and Children (WIC). Prior research documents long-term benefits from programs similar to each of these elements ..."
anigbrowl 9y ago
It's a really strong study. N= ~1500, the cost-benefit ratio from remediation in improved education outcomes and lower social costs of crime is 1.8. Probably 1 million children across the US have been impacted by elevated blood lead levels over the last 20 years. there is no good reason to postpone acting on this problem, which is well understood by now. https://www.dropbox.com/s/07z65p9a5wdppfl/LifeAfterLead_AEJ_Revision_3_16_17.pdf?dl=0 https://www.dropbox.com/s/07z65p9a5wdppfl/LifeAfterLead_AEJ_...
- malandrew 9y ago
  Wow. Those are some remarkable results. I've hypothesized for a while now that the Black Lives Matter movement might be distracting us from what might be the true cause of the problems they seek to address. Blaming the problem on "racist" cops by default instead of performing a root cause analysis is leading us to overlook the likelihood that poorer communities, that are often predominantly black, are more likely to be exposed to lead. http://www.huffingtonpost.com/2015/07/13/black-children-at-risk-for-lead-poisoning-_n_7672920.html http://www.huffingtonpost.com/2015/07/13/black-children-at-r...
  - astrodust 9y ago
    Exposure leads to behaviour modification which leads to law enforcement over-generalizing behaviour patterns they've observed. It will take some time to unwind this terrible mess even if the lead problem is eliminated entirely tomorrow. This doesn't mean the cops aren't racist and that lead isn't a problem.
    - malandrew 9y ago
      Agree mostly. However, is it actually an overgeneralization if it is statistically proportional with rate of violent crime: https://ucr.fbi.gov/crime-in-the-u.s/2014/crime-in-the-u.s.-2014/tables/table-43 https://ucr.fbi.gov/crime-in-the-u.s/2014/crime-in-the-u.s.-...
    - 13of40 9y ago
      I'm sure this probably isn't the case, but what if lead exposure made you more likely to get caught for a crime but didn't affect the chances of committing one? Are there any all-else-being-equal studies that can tell us whether violent crime is higher in areas with a high rate of lead exposure?
Romanulus 9y ago
Isn't this just a roundabout way of saying that people with lower IQs are more prone to criminal activity?
- Symmetry 9y ago
  My understanding is that lead exposure increases impulsiveness much more than you would expect from the IQ decrease it also causes.
- ceejayoz 9y ago
  Lead poisoning comes with more than just an IQ drop - it increases aggression and reduces impulse control.
- nabla9 9y ago
  No. Low IQ is just one effect. Low impulse control is most likely cause for criminality. Neurological and Behavioral Consequences of Childhood Lead Exposure https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2689677/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2689677/ >The underlying common pathway for all of these associations might be lead's adverse effects on executive functioning [19–21], resulting in poor impulse control. Low impulse control in general seems to be one of the is the strongest predictors of criminal behaviour, whatever the cause. sources: http://journals.sagepub.com/doi/10.1177/0093854806292299 http://journals.sagepub.com/doi/10.1177/0093854806292299 http://onlinelibrary.wiley.com/doi/10.1111/j.1745-9125.2000.tb00911.x/abstract http://onlinelibrary.wiley.com/doi/10.1111/j.1745-9125.2000....
- nerpderp83 9y ago
  No. Look at people with Down-Syndrome, they are extremely thoughtful and nice. Least likely to commit a violent act or partake in criminal activity.
  - VladKovac 9y ago
    there's a sweet spot, obviously if you go too low you're talking about barely autonomous people
- 9y ago
erentz 9y ago
This still affects a lot of communities in California. [1] (And, of course elsewhere across the country.) [1] http://www.reuters.com/article/us-usa-lead-california-exclusive-idUSKBN16T18Y http://www.reuters.com/article/us-usa-lead-california-exclus...
jbg_ 9y ago
Can anyone explain to me why the group that had high exposure but an intervention that reduced their exposure to about 5 on the graph, has much lower violent crime levels than the group that had an exposure of around 5 and no intervention?
- d0mine 9y ago
  "the sample sizes are fairly modest" -> large variance? Plus, obvious results don't make the news https://www.xkcd.com/882/ https://www.xkcd.com/882/
- sloppycee 9y ago
  That does seem like an issue with the study, from the pdf: "Two primary channels emerge through which intervention affects antisocial behavior and cognitive outcomes. First, intervention may dramatically reduce the amount of continued childhood exposure to the dangerous neurotoxin by directly reducing exposure risks within the home environment. Second, long-term benefits may occur through improvements in early-life health unrelated to any changes in lead exposure. [11] ... [11] The elevated BLL intervention package includes treatments previously demonstrated to impact later-life outcomes such as: visits from health workers; increased medical care; nutritional assessments and dietary modifications; and referral to the Special Supplemental, Nutrition Program for Women, Infants, and Children (WIC). Prior research documents long-term benefits from programs similar to each of these elements ..." Why didn't they control for the other intervention treatments? One where they reduce BLL + other treatments, and one where they didn't reduce BLL but still gave the other treatments?
  - btilly 9y ago
    This is a reasonable question which has some very good answers. The data is from a program that aimed to mitigate problems from high lead. The program's primary aim wasn't to allow papers to be published about their research goal many years later. You make the best use that you can of the data that you've got. And don't insist on the perfect data that you don't have. But even if this had been designed as a pure research program, the design that you suggest would never be approved on ethical grounds. We accumulated enough data many years ago on the negative impact of lead that we cannot in good conscience withhold treatment for the sake of collecting better data. Review the history of the Tuskegee Study for an example of why such ethical guidelines were put in place.
mrfusion 9y ago
comment deleted
- astrodust 9y ago
  If only there were some kind of service where one could type in queries like this and receive answers...
  - HankB99 9y ago
    There are! I Googled for "online query answerer" and there were 131,000 results.
theprop 9y ago
Wow, yes, could be very true!! Could be related to higher crime rates by certain minority groups that may tend to live in old homes with lead paint. Historically, the great great great painter Caravaggio was quite violent/irritable and died sadly so so young (30 something) and many theories are that he was quite irritable/violent because of lead poisoning (he was prolific, working all the time with lead points).
- anigbrowl 9y ago
  Definitely true. Nowadays painters use bleached titanium to get a brilliant white, but until the late 19th century lead salts were the norm. Basically you hammer out ingots of lead into flat strips, roll them up into a cylinder, and seal them in ceramic jars full of vinegar for 6 months. When you take them out the lead has turned white and is them ground up into powder and mixed with oil. You can still get this from a few specialty suppliers and it's reasonably safe to use as long as you wear gloves paint slowly enough that you don't get it all over your skin. Ingested lead is much more dangerous than skin contact, and of course the process of grinding the treated strips of lead into powder was a respiratory and gastric disaster - although people were not completely clueless and apprentices in art studios would often cover their lower face with a wet cloth.
jostmey 9y ago
Scary that airplanes are still allowed to use leaded fuel. Somehow society is stuck between the information age and the stupid age. https://www.scientificamerican.com/article/lead-in-aviation-fuel/ https://www.scientificamerican.com/article/lead-in-aviation-...
- korethr 9y ago
  It may be helpful to ask why. Why might aviation engines still be using leaded gasoline? If one knew why avgas was still leaded, that might point to possible practical, implementable solutions. Yes, laziness, ignorance, stupidity, incompetence, malice, etc, are all possibly valid answers to "Why?". But accepting such answers without scrutiny when another answer may be closer to the truth is a bad habit, IMO. If you were to come into a legacy codebase at work and assume that the previous authors incompetent idiots, you'd probably be less productive than if you assumed that the previous authors had problems to solve and chose the best option available to them given the constraints at the time. Keeping in mind past and current goals, and past and current constraints is probably going to get you further than, "This is bad! Change it!"
- entee 9y ago
  A quick check on wikipedia quotes: "Current aircraft engines feature valve gear components which are designed for compatibility with the leaded ASTM D910 fuels. In such fuels, the lead acts as a lubricant, coating the contact areas between the valve, guide, and seat. The use of unleaded auto fuels with engines designed for leaded fuels can result in excessive exhaust valve seat wear due to the lack of lead. The result can be remarkable, with cylinder performance deteriorating to unacceptable levels in under 10 hours." https://web.archive.org/web/20120413123438/http://www.tcmlink.com:80/visitors/carenfeed/engoperhdr.cfm https://web.archive.org/web/20120413123438/http://www.tcmlin... Also lead is an anti-knock agent so it is used to get to the very high octane ratings in Avgas. And it seems the problem may be solved soon! "By May 2012, the US Federal Aviation Administration (FAA Unleaded Avgas Transition rulemaking committee) had put together a plan in conjunction with industry to replace leaded avgas with an unleaded alternative within 11 years. Given the progress already made on 100SF and G100UL, the replacement time might be shorter than that 2023 estimate." https://en.wikipedia.org/wiki/Avgas https://en.wikipedia.org/wiki/Avgas
nerpderp83 9y ago
Chicago needs to fix this.
renega3 9y ago
Considering it's the basis of the entire hypothesis, here's the nature of the intervention: All cases with two BLL tests exceeding the alert threshold (10 ug/dL) trigger eligibility for an intervention which includes the following actions: education for caregivers (which includes nutritional advice and information about reducing exposure in the home); a voluntary home environment investigation; and a referral to lead remediation services. A more intensive intervention can be triggered by tests over 15 ug/dL or 20 ug/dL. In addition to educating caregivers and providing a referral to remediation services, the intensive intervention typically includes: a mandatory home environment investigation; nutritional assessment; medical evaluation; developmental assessment; and a referral to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC)
lsiebert 9y ago
Efforts to reduce lead exposure in the 1980s arguably were behind much of the lower crime rates in the 1990s and 2000's that we've seen. There are other studies cited in relevant wikipedia articles like https://en.wikipedia.org/wiki/Crime_in_the_United_States#cite_note-13 https://en.wikipedia.org/wiki/Crime_in_the_United_States#cit... And yes, crime rates are significantly lower adjusting for population, though that's not always conveyed accurately by those in authority and the news media.
Bakary 9y ago
It's sad how deterministic our lives really are.

210 points by curtis 9y ago

rntz 9y ago

The article title on the original site was changed from "... Confirms the Lead-Crime Hypothesis" to "... Bolsters the Lead-Crime Hypothesis", since "It's a good study, but it's still just one more study." Title here should be changed likewise.

sctb 9y ago
Thank you, we've updated the headline here.

douche 9y ago

The lead-violence correlation is very, very interesting. What always makes me wonder is how much historical effect environmental factors like this must have had. Lead used to be ubiquitous, between paint, pipes, roofing, glass, solder - the Romans even cooked in lead vessels at times. There's probably no way of ever teasing out all the different factors, but when you read accounts of what daily life was like in, say 18th century London, and a.) violence was quite common-place, and b.) virtually everyone kept themselves inebriated enough to fail a breathalyzer at all times. Probably b.) contributed a good deal to a.), but if everybody is also suffering from low-level chronic lead poisoning...

snovv_crash 9y ago
Never mind cooking in lead vessels, they used lead acetate as an artificial sweetener in their food. I've often wondered if this was something that contributed to their downfall.
- wil421 9y ago
  I'm sure it didn't help Caligula. It seems a lot of crazy acting emperors could be linked to lead poisoning. It makes me think what people 50-100 years will think about our diets. They put sugar in everything!
  - tcoppi 9y ago
    More likely to be the huge amount of plasticizers that have been making their way into our diet, imo.
  - AnimalMuppet 9y ago
    You know, it would explain a lot of things if, over the last 10 or 20 years, something were slowly driving more and more people crazy...
    - posterboy 9y ago
      The Opium epidemic lead to a freaking trade war [1]. How about crack cocaine and other designer drugs, incl. highly potent cannabis, alcohol and cigarettes as factors? [1]: https://en.wikipedia.org/wiki/Opium_Wars https://en.wikipedia.org/wiki/Opium_Wars
- Tharkun 9y ago
  What makes it worse is that the Romans knew lead was toxic. But they thought its effect was limited to the production process, which was mostly done by slaves and other people of no apparent value.
naasking 9y ago
Crime and violence has been falling steadily over the past century too. Makes you wonder if this significant social change isn't because of better education, social programs, etc., but simply because of other factors like this that we're simply unaware of.
- ceejayoz 9y ago
  As pointed out elsewhere in the thread, different countries phased out tetraethyl lead in gasoline at different times, and their respective drops in crime correlate well with those dates.
- Gibbon1 9y ago
  No one disputes that other factors are important. For instance cultural attitudes about violence are important. As is the reach of civil government. Not to mention that in the US violence is a particular problem because of ready access to handguns. My take having read about this theory for about ten years now it looks like the preponderance of the evidence says that lead exposure is at least as significant as the above. Meaning it's not just this study, it's all the other ones as well. With the lead thoery you have the following. 1. A known mechanism. Lead cause brain damage with poor impulse control. 2. Dose response correlation between lead exposure and violent crime. Thing that freaks me out is what did exposure to lead and resulting poor impulse control do to politics in the US.
- bjourne 9y ago
  It hasn't. See this graph f.e https://ourworldindata.org/wp-content/uploads/2013/03/homicide-rates-in-the-united-states-1950-2010-and-canada-1961-2009-pinker-2011-jpg.jpg https://ourworldindata.org/wp-content/uploads/2013/03/homici... In many countries, violent crime exploded in the late 1960s and then increased until the mid 1990s after which it began decreasing again.

alexilliamson 9y ago

From the article: "The statistical significance of the drop is extremely strong" I haven't read the source paper yet, but the way this is phrased makes me skeptical of the strength of these findings. Having worked briefly on a lead remediation project for a city government who has been in the news recently for lead, I can tell you that this is a really tough question and the confounding factors are huge. The political consequences mean that folks have incentive to seriously overstate (or understate) the importance and validity of a study like this.

anigbrowl 9y ago
I really think you ought to read it before making such a dismissive comment.
nabla9 9y ago
There have been several studies over the years and the evidence is strong. Crime rates seem to drop with 20 year lag after TEL phaseout in gasoline starts. Different countries banned TEL at different times and it's very hard to deny connection.
sloppycee 9y ago
Unfortunate that you're being down-voted for being skeptical, this study does have some issues confounding the results: "The elevated BLL intervention package includes treatments previously demonstrated to impact later-life outcomes such as: visits from health workers; increased medical care; nutritional assessments and dietary modifications; and referral to the Special Supplemental, Nutrition Program for Women, Infants, and Children (WIC). Prior research documents long-term benefits from programs similar to each of these elements ..."

anigbrowl 9y ago

It's a really strong study. N= ~1500, the cost-benefit ratio from remediation in improved education outcomes and lower social costs of crime is 1.8. Probably 1 million children across the US have been impacted by elevated blood lead levels over the last 20 years. there is no good reason to postpone acting on this problem, which is well understood by now. https://www.dropbox.com/s/07z65p9a5wdppfl/LifeAfterLead_AEJ_Revision_3_16_17.pdf?dl=0 https://www.dropbox.com/s/07z65p9a5wdppfl/LifeAfterLead_AEJ_...

malandrew 9y ago
Wow. Those are some remarkable results. I've hypothesized for a while now that the Black Lives Matter movement might be distracting us from what might be the true cause of the problems they seek to address. Blaming the problem on "racist" cops by default instead of performing a root cause analysis is leading us to overlook the likelihood that poorer communities, that are often predominantly black, are more likely to be exposed to lead. http://www.huffingtonpost.com/2015/07/13/black-children-at-risk-for-lead-poisoning-_n_7672920.html http://www.huffingtonpost.com/2015/07/13/black-children-at-r...
- astrodust 9y ago
  Exposure leads to behaviour modification which leads to law enforcement over-generalizing behaviour patterns they've observed. It will take some time to unwind this terrible mess even if the lead problem is eliminated entirely tomorrow. This doesn't mean the cops aren't racist and that lead isn't a problem.
  - malandrew 9y ago
    Agree mostly. However, is it actually an overgeneralization if it is statistically proportional with rate of violent crime: https://ucr.fbi.gov/crime-in-the-u.s/2014/crime-in-the-u.s.-2014/tables/table-43 https://ucr.fbi.gov/crime-in-the-u.s/2014/crime-in-the-u.s.-...
  - 13of40 9y ago
    I'm sure this probably isn't the case, but what if lead exposure made you more likely to get caught for a crime but didn't affect the chances of committing one? Are there any all-else-being-equal studies that can tell us whether violent crime is higher in areas with a high rate of lead exposure?

Romanulus 9y ago

Isn't this just a roundabout way of saying that people with lower IQs are more prone to criminal activity?

Symmetry 9y ago
My understanding is that lead exposure increases impulsiveness much more than you would expect from the IQ decrease it also causes.
ceejayoz 9y ago
Lead poisoning comes with more than just an IQ drop - it increases aggression and reduces impulse control.
nabla9 9y ago
No. Low IQ is just one effect. Low impulse control is most likely cause for criminality. Neurological and Behavioral Consequences of Childhood Lead Exposure https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2689677/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2689677/ >The underlying common pathway for all of these associations might be lead's adverse effects on executive functioning [19–21], resulting in poor impulse control. Low impulse control in general seems to be one of the is the strongest predictors of criminal behaviour, whatever the cause. sources: http://journals.sagepub.com/doi/10.1177/0093854806292299 http://journals.sagepub.com/doi/10.1177/0093854806292299 http://onlinelibrary.wiley.com/doi/10.1111/j.1745-9125.2000.tb00911.x/abstract http://onlinelibrary.wiley.com/doi/10.1111/j.1745-9125.2000....
nerpderp83 9y ago
No. Look at people with Down-Syndrome, they are extremely thoughtful and nice. Least likely to commit a violent act or partake in criminal activity.
- VladKovac 9y ago
  there's a sweet spot, obviously if you go too low you're talking about barely autonomous people
9y ago

erentz 9y ago

This still affects a lot of communities in California. [1] (And, of course elsewhere across the country.) [1] http://www.reuters.com/article/us-usa-lead-california-exclusive-idUSKBN16T18Y http://www.reuters.com/article/us-usa-lead-california-exclus...

jbg_ 9y ago

Can anyone explain to me why the group that had high exposure but an intervention that reduced their exposure to about 5 on the graph, has much lower violent crime levels than the group that had an exposure of around 5 and no intervention?

d0mine 9y ago
"the sample sizes are fairly modest" -> large variance? Plus, obvious results don't make the news https://www.xkcd.com/882/ https://www.xkcd.com/882/
sloppycee 9y ago
That does seem like an issue with the study, from the pdf: "Two primary channels emerge through which intervention affects antisocial behavior and cognitive outcomes. First, intervention may dramatically reduce the amount of continued childhood exposure to the dangerous neurotoxin by directly reducing exposure risks within the home environment. Second, long-term benefits may occur through improvements in early-life health unrelated to any changes in lead exposure. [11] ... [11] The elevated BLL intervention package includes treatments previously demonstrated to impact later-life outcomes such as: visits from health workers; increased medical care; nutritional assessments and dietary modifications; and referral to the Special Supplemental, Nutrition Program for Women, Infants, and Children (WIC). Prior research documents long-term benefits from programs similar to each of these elements ..." Why didn't they control for the other intervention treatments? One where they reduce BLL + other treatments, and one where they didn't reduce BLL but still gave the other treatments?
- btilly 9y ago
  This is a reasonable question which has some very good answers. The data is from a program that aimed to mitigate problems from high lead. The program's primary aim wasn't to allow papers to be published about their research goal many years later. You make the best use that you can of the data that you've got. And don't insist on the perfect data that you don't have. But even if this had been designed as a pure research program, the design that you suggest would never be approved on ethical grounds. We accumulated enough data many years ago on the negative impact of lead that we cannot in good conscience withhold treatment for the sake of collecting better data. Review the history of the Tuskegee Study for an example of why such ethical guidelines were put in place.

mrfusion 9y ago

comment deleted

astrodust 9y ago
If only there were some kind of service where one could type in queries like this and receive answers...
- HankB99 9y ago
  There are! I Googled for "online query answerer" and there were 131,000 results.

theprop 9y ago

Wow, yes, could be very true!! Could be related to higher crime rates by certain minority groups that may tend to live in old homes with lead paint. Historically, the great great great painter Caravaggio was quite violent/irritable and died sadly so so young (30 something) and many theories are that he was quite irritable/violent because of lead poisoning (he was prolific, working all the time with lead points).

anigbrowl 9y ago
Definitely true. Nowadays painters use bleached titanium to get a brilliant white, but until the late 19th century lead salts were the norm. Basically you hammer out ingots of lead into flat strips, roll them up into a cylinder, and seal them in ceramic jars full of vinegar for 6 months. When you take them out the lead has turned white and is them ground up into powder and mixed with oil. You can still get this from a few specialty suppliers and it's reasonably safe to use as long as you wear gloves paint slowly enough that you don't get it all over your skin. Ingested lead is much more dangerous than skin contact, and of course the process of grinding the treated strips of lead into powder was a respiratory and gastric disaster - although people were not completely clueless and apprentices in art studios would often cover their lower face with a wet cloth.

jostmey 9y ago

Scary that airplanes are still allowed to use leaded fuel. Somehow society is stuck between the information age and the stupid age. https://www.scientificamerican.com/article/lead-in-aviation-fuel/ https://www.scientificamerican.com/article/lead-in-aviation-...

korethr 9y ago
It may be helpful to ask why. Why might aviation engines still be using leaded gasoline? If one knew why avgas was still leaded, that might point to possible practical, implementable solutions. Yes, laziness, ignorance, stupidity, incompetence, malice, etc, are all possibly valid answers to "Why?". But accepting such answers without scrutiny when another answer may be closer to the truth is a bad habit, IMO. If you were to come into a legacy codebase at work and assume that the previous authors incompetent idiots, you'd probably be less productive than if you assumed that the previous authors had problems to solve and chose the best option available to them given the constraints at the time. Keeping in mind past and current goals, and past and current constraints is probably going to get you further than, "This is bad! Change it!"
entee 9y ago
A quick check on wikipedia quotes: "Current aircraft engines feature valve gear components which are designed for compatibility with the leaded ASTM D910 fuels. In such fuels, the lead acts as a lubricant, coating the contact areas between the valve, guide, and seat. The use of unleaded auto fuels with engines designed for leaded fuels can result in excessive exhaust valve seat wear due to the lack of lead. The result can be remarkable, with cylinder performance deteriorating to unacceptable levels in under 10 hours." https://web.archive.org/web/20120413123438/http://www.tcmlink.com:80/visitors/carenfeed/engoperhdr.cfm https://web.archive.org/web/20120413123438/http://www.tcmlin... Also lead is an anti-knock agent so it is used to get to the very high octane ratings in Avgas. And it seems the problem may be solved soon! "By May 2012, the US Federal Aviation Administration (FAA Unleaded Avgas Transition rulemaking committee) had put together a plan in conjunction with industry to replace leaded avgas with an unleaded alternative within 11 years. Given the progress already made on 100SF and G100UL, the replacement time might be shorter than that 2023 estimate." https://en.wikipedia.org/wiki/Avgas https://en.wikipedia.org/wiki/Avgas

nerpderp83 9y ago

Chicago needs to fix this.

renega3 9y ago

Considering it's the basis of the entire hypothesis, here's the nature of the intervention: All cases with two BLL tests exceeding the alert threshold (10 ug/dL) trigger eligibility for an intervention which includes the following actions: education for caregivers (which includes nutritional advice and information about reducing exposure in the home); a voluntary home environment investigation; and a referral to lead remediation services. A more intensive intervention can be triggered by tests over 15 ug/dL or 20 ug/dL. In addition to educating caregivers and providing a referral to remediation services, the intensive intervention typically includes: a mandatory home environment investigation; nutritional assessment; medical evaluation; developmental assessment; and a referral to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC)

lsiebert 9y ago

Efforts to reduce lead exposure in the 1980s arguably were behind much of the lower crime rates in the 1990s and 2000's that we've seen. There are other studies cited in relevant wikipedia articles like https://en.wikipedia.org/wiki/Crime_in_the_United_States#cite_note-13 https://en.wikipedia.org/wiki/Crime_in_the_United_States#cit... And yes, crime rates are significantly lower adjusting for population, though that's not always conveyed accurately by those in authority and the news media.

Bakary 9y ago

It's sad how deterministic our lives really are.