While roaming the Internet, I stumbled across this article. It’s from 2007, but its contents are still very relevant:

[…] Through much of the 20th century, lead in U.S. paint and gasoline fumes poisoned toddlers as they put contaminated hands in their mouths. The consequences on crime, Nevin found, occurred when poisoning victims became adolescents. […E]vidence has accumulated in recent years that lead is a neurotoxin that causes impulsivity and aggression […]. In 2002, Herbert Needleman, a psychiatrist at the University of Pittsburgh, compared lead levels of 194 adolescents arrested in Pittsburgh with lead levels of 146 high school adolescents: The arrested youths had lead levels that were four times higher. […]

While I read it, the thing that kept popping into my head was some mention I’d heard of a theory that the Roman Empire fell in part because the aquaducts were all made of lead, and all the water the citizens drank ran through them.

It also occurred to me to check the dates of the US’s “two spikes of lead poisoning” mentioned. The most recent was after World War II (which ended in 1945, and was followed by a sharp increase in the use of leaded gasoline) and apparently kept going through the mid-1970s (when the majority of leaded gasoline was phased out nationally), so people roughly forty to seventy now got the brunt of it. I tried to find correllations with different political groups and social trends, but the only notable one I saw was the prevalence of really tacky decor in the seventies.

(Via Druid Journal)