Element number 82 is the heaviest non-radioactive element and constitutes about 14 parts per million in the Earth's crust. It's easily smelted and has been in use for millenia. It's also a potent neurotoxin.
Kevin Drum has been championing the view that lead, and in particular its use in paint and gasoline additives is a key factor in explaining some otherwise puzzling crime statistics. See America's Real Criminal Element, and some high praise here.
A sample of the former:
IN 1994, RICK NEVIN WAS A CONSULTANT working for the US Department of Housing and Urban Development on the costs and benefits of removing lead paint from old houses. This has been a topic of intense study because of the growing body of research linking lead exposure in small children with a whole raft of complications later in life, including lower IQ, hyperactivity, behavioral problems, and learning disabilities.
But as Nevin was working on that assignment, his client suggested they might be missing something. A recent study had suggested a link between childhood lead exposure and juvenile delinquency later on. Maybe reducing lead exposure had an effect on violent crime too?
That tip took Nevin in a different direction. The biggest source of lead in the postwar era, it turns out, wasn't paint. It was leaded gasoline. And if you chart the rise and fall of atmospheric lead caused by the rise and fall of leaded gasoline consumption, you get a pretty simple upside-down U: Lead emissions from tailpipes rose steadily from the early '40s through the early '70s, nearly quadrupling over that period. Then, as unleaded gasoline began to replace leaded gasoline, emissions plummeted.
The web of evidence tightens.
Twenty years ago that kind of detective work took a lot of luck and ingenuity. In the age of big data, these kinds of correlations are probably all over the place.
The moralistically inclined tend to be skeptical, because if crime is caused by biological damage to the developing brain, it gets a lot harder to blame it on Satan, television, and your political opponent - unless that opponent opposed plans to eliminate lead additives.