People have theorized for years about what might have caused the crime wave of the '60s through '90s, and what curbed it, but a new study suggests that the whole phenomenon was automotive in nature. When lead gets into the bloodstream, in addition to the well publicized loss of IQ, it also damages the prefrontal cortex, which is responsible for impulse control, emotional regulation, verbal reasoning, attention, aggression control, and mental flexibility; basically all the stuff that makes you not a violent criminal happens there.
What has been found is that a couple of decades after the car became commonplace in the post-war period, violent crime rates went up, because the babies born in this car boom had higher blood-lead levels. After leaded gasoline was banned, the rates dropped. What is compelling about this is that crime rates have followed this same pattern in other countries that banned leaded gasoline at different times.
The problem now is that all that lead has settled in our soil and, especially in urban and poorer areas, little has been done to clean it up and the concentration is quite high. In the summer, when the soil dries up, a lot of this gets kicked up into the air.
Now obviously, crime isn't due only to blood-lead levels, but it could certainly push a generation over the edge.
To really get the lead out of the system, we'd have to spend about $20 billion annually, according to Mother Jones, but the annual return from the higher incomes of more intelligent children and the reduced cost of crime would be about $210 billion.
[via Mother Jones]