[achy]

It's always interesting when statistics correlate across multiple frames (time, location, etc.); however that still doesn't prove causality. I'm inclined to think that the causes behind an area being slow to remove leaded gasoline could also affect crime rates.

[edmccard]

>I'm inclined to think that the causes behind an area being slow to remove leaded gasoline could also affect crime rates.

The statistics show a 20-year lag between the banning of leaded gasoline and reduction in crime rates. So even if "unwilling to ban leaded gas" and "high crime 20 years later" could be correlated, it seems less likely that the same things that cause "willing to ban leaded gas" are also the cause of "lower crime 20 years later".

[originofspecie]

That's not entirely true. One factor could be that less progressive urban areas are both less willing to remove lead from gasoline and less willing to fund community outreach programs. Community out reach programs may take years to gain traction and become effective. Banning gasoline is witnessed in a much shorter time frame. This would explain the lag between crime rate drops and banning of leaded gasoline.

[VLM]

Its interesting to model the biosphere hydraulically.

So lead from leaded gas drips into the barrel representing the local ecology, and the lead contaminant drips out of the biosphere at a rate that obviously must depend on local climate. Presumably lead contaminant flows into the oceans or gets buried in the ground at a rate dependent on local weather.

Yet the stats show a nearly perfect and consistent shift 20 years after the addition of lead to the environment stops. That's just biologically weird, like a part of brain development doesn't depend on local lead levels, but on the first derivative of lead levels or something.

It COULD make sense if lead only causes problems when inhaled. Not consumed in food, not drinking water, purely and exclusively inhaled. Even then, local dust storms and the like should totally mess with the supposed global 20 year effect latency.

[Terr_]

Lead reacts with other elements! If it was as un-reactive as gold, it probably wouldn't be as toxic.

Just for starters, burning leaded gasoline can involve pure Lead, Lead(II) oxide, Lead(II) bromide, and Lead(II) chloride.

http://en.wikipedia.org/wiki/Tetraethyllead#Reactions

[edmccard]

>It COULD make sense if lead only causes problems when inhaled

I think inhalation of engine exhaust is the main "delivery method" for lead pollution from leaded gasoline.