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[smjjames]

Lead cars? lol, they'd probably barely be able to move.

@ Loud Whispers: The Romans already did that, sort of. However, good data on crime rates back then would be difficult, if not impossible to come by. Plus it was kind of a constant exposure, not a sudden *boop* now we have lead stuff in the middle of the empire's existence.

[Reelya]

"As mad as a hatter", and the Mad Hatter from Alice in Wonderland also have their root in lead poisoning. In the 18th-19th century Britain, the stiff rims of gentleman's hats were laced with lead. Most hatters went batshit insane in their later years from the effects of lead poisoning.

Sorry, but that was mercury poisoning, not lead.

• Cancer rates fall.

Unfortunately, lead is also carcinogenic, offseting any "shielding" effect from radiation. While they're not sure of the exact mechanism, people have a higher probability of cancer deaths if they have high blood lead levels.

[Helgoland]

Radioactive lead isotopes?

[smeeprocket]

It's well known that lead is very poisonous and can cause neurological problems, especially in young children, so we should not be exposing people to it regardless of whether it's responsible for long-term crime trends.  With that said though, I find a lot of these analyses very dubious.  The UK banned unleaded paint in 1992, and petrol in 1998 (as far as I can tell no serious move was made to even reduce the usage of it until the late 80s).  Under the "Banning lead causes crime rates to drop 23 years later" hypothesis you'd expect violent crime in the UK to still be rising, or at best for the trend to have reversed just a few years ago.  This isn't the case however - in actual fact the violent crime rate began to drop in the early 90s, just like in the US.

http://news.bbc.co.uk/1/hi/uk/7511807.stm

The USA banned leaded fuel in 1996. They had a similar lead-time, therefore it's not a discrepancy. 1996 vs 1998 is pretty close.

But the USA brought in unleaded in 1976, and the UK only brought in unleaded in 1986!

That sounds like a problem but then you can find citations to say that the UK cut allowable lead fuel concentations in half starting in 1976, from 0.84 g/l to 0.4 g/l, then they cut them again to 0.15 g/l in 1986. So the dates should actually correlate with the USA data. Both countries had 20 years of phasing down lead concentrations in leaded fuels. While the USA brought in unleaded a bit earlier, they were actually coming down from a higher concentration of lead than the UK, it started at ~1.05 g/l in the USA

Spoiler: UK 1976 phase out lead citation (click to show/hide)

http://www.eea.europa.eu/publications/late-lessons-2/late-lessons-chapters/late-lessons-ii-chapter-3/at_download/file

EU policymaking on leaded petrol emerged mainly from the activities of the UK and Germany. In 1971, the UK government received advice from its Chief Medical Officer that air lead levels should not be allowed to increase above current levels. The government responded by deciding on a phased three stage reduction in petrol's lead content, from 0.84 to 0.4 g/l to be achieved in 1976.

Similar with paint, once, it was normal for leaded paints to be up to 50% lead, but by the end, it was a small percentage:
http://www.environment.gov.au/protection/publications/factsheet-lead-alert-facts-lead-house-paint

The recommended amount of lead in domestic paint has declined from 50% before 1965, to 1% in 1965. In 1992, it was reduced to 0.25%, and in 1997 it was further reduced to 0.1%. So, when you say "lead in paint" it dropped by a factor of 50 between the end of WWII and 1965. Current "leaded" paint is 500 times less lead than the 1950's lead paint. So the UK 1992 ban on leaded paint was the end of a long series of reductions anyway.

I thought, within the past five years, congress actually raised the allowable lead in paint. I remember because I thought it was such an insane move, and was no doubt completely based off of lobbying.

[Sheb]

Lead actually isn't carcinogenic. The IARC classify it in the same group as magnets, mobile phone radiation and bracken fern. Toxic yeah, but it can kill you without cancer.

[Graknorke]

Magnets are toxic?

[Sheb]

No, they're not. That's the point.

[Reelya]

That's a list of "probably" carcinogenic things. So the available evidence says that exposure is correlated with cancer, but the evidence isn't sufficient to prove a causal link.

In clinical studies with rats, lead compounds are strongly associated with cancer of the kidneys. We can't really do those studies on humans to prove a link though. Human lead exposure is definitely correlated with a number of cancers, but we can't rule out other causes yet.

For bracken, it does contain a known carcinogen, but the traditional methods of cooking it remove almost all of this compound:
http://www.theatlantic.com/health/archive/2011/06/the-bracken-fern-a-natural-born-killer/241271/

    First, it is water soluble. That means if you soak bracken fiddleheads in cool water (cool to keep them crunchy), and change that water every so often, you will greatly reduce the level of ptalquiloside in the fiddlehead; the Japanese often eat bracken this way.
    Second, ptalquiloside is notoriously volatile at normal temperatures. The pure stuff degenerates at room temperature, which is why the scientists doing the rat studies store their palquiloside at -20 degrees Celsius. Once exposed to boiling temperatures, the carcinogen denatures almost completely. Salt and baking soda increase this effect.

What this means is that a very normal cooking process for fiddleheads—blanching in salty water, then shocking in ice water, then sauteeing—renders the fiddlehead close to harmless.

Note that I say "close to harmless." The reason we know that bracken can cause cancer is not only because of all sorts of livestock studies—cows sometimes eat the fully grown fronds and get urinary tract cancers—but also because bracken is widely eaten in Korea, Japan and parts of China. And when I mean "widely," I mean almost every day in some cases. Bracken (gosari) is a classic part of bibimbap, one of the most famous Korean dishes there is.

Most of the research has been done by Japanese and Koreans, searching for clues as to why they seem to have high rates of throat and stomach cancer. Apparently there are a kaleidoscope of reasons, and habitual bracken-eating is among them.

[Sheb]

Yeah, although the IARC only every designed one substance it studied as "non-carcinogenic". So that category is pretty safe.

[Reelya]

That's sort of a misleading statement given the numbers:

Group 1    Carcinogenic to humans    114 agents
Group 2A    Probably carcinogenic to humans      69
Group 2B     Possibly carcinogenic to humans    283
Group 3    Not classifiable as to its carcinogenicity to humans                504
Group 4    Probably not carcinogenic to humans         1

You've ommitted "group 3" substances, which is the biggest group. A lot of the 2B substances do appear to cause cancer in lab animals, but of course that's not proof that cancers in humans are caused by the same thing. The IARC also gets criticism for being a "rubber stamp" for industry pollutants. Even one of their previous directors accuses the organization of covering up carcinogens because of industry pressure. So, the categories should be seen as an absolute minimum.

[Flying Dice]

I can't believe how everyone is mixing up cause and effect. Obviously a high violent crime rate leads to increased incidence of lead poisoning.

Spoiler (click to show/hide)

Because of all the people getting shot huehuehue.

Seriously though, PTW.

[MDFification]

The IARC also gets criticism for being a "rubber stamp" for industry pollutants. Even one of their previous directors accuses the organization of covering up carcinogens because of industry pressure. So, the categories should be seen as an absolute minimum.

Aye, that's why we've got a known carcinogenic dye approved for human consumption in food.

[TamerVirus]

For a moment I thought that this was just going to be about getting shot.

You know, Lead poisoning, 10cc injections.

[Reelya]

That's possible though, there could be some instances of vicious circle: dude grows up violent due to lead poisoning, takes up shooting, gets more contamination at the shooting range. Firing ranges etc do have a lot of lead contamination. Yet another good reason not to take you pregnant wife and toddlers to the shooting range.

[wierd]

Bismuth is a perfectly acceptable alternative to lead for use in projectile weapons, however the cost of the metal makes shooting with it prohibitive.

The obvious connection with surface water body contamination with lead compounds and sport waterfowl hunting with firearms is the reason for legislation that aims to mitigate this exposure as much as possible. It is not legal to use unjacketed lead shot to hunt waterfowl. One must use copper jacketed lead shot (Very bad for gun barrels, especially antique black powder models, which have softer steels in the barrel which become eroded from the abrasive action of the copper jacketed shot pellets), or use the expensive bismuth shot.

Considering that bismuth is not that rare of a metal, I really don't understand why it is so expensive per pound, but it is. It may have something to do with bismuth having more applications in medicinal preparations (Peptobismol is bismuth subsalicylate, sodium saccharine, water, red #40, Blue #2, and wintergreen flavoring.)  and in chemical processes that drive up its demand, but I would need to see data to that effect.


Edit:

The point to the above that I got lost in the particulars of-- Shooting ranges need not necessarily be contaminated with lead, they typically are because of the lack of affordable alternatives, even though suitable alternatives most certainly exist.