Violent Crime, IQ, and... Lead

Kevin Drum for Mother Jones recently published a piece on the diabolical influence of lead molecules on human society. Drum translates into journalistic language the hypothesis of Rick Nevin, who has argued that ingested lead levels, largely a byproduct of the tremendous sales of leaded gasoline after World War II, offers a staggeringly compelling correlation with violent crime rates in the United States. After the EPA was created and started demanding stricter emissions controls, such the catalytic converter, the sale and use of leaded gasoline declined dramatically. By 1996, the final phase out in the United States for motor vehicles occurred. High crime levels in the 1970s and 1980s, especially in big cities (where lead levels in the air were higher) dropped in the 1990s as generations of children came into adulthood who had ingested far less lead.

Setting aside its effects on violent tendencies, Drum notes that lead does lasting damage to the intelligence:

Neurological research is demonstrating that lead's effects are even more appalling, more permanent, and appear at far lower levels than we ever thought. For starters, it turns out that childhood lead exposure at nearly any level can seriously and permanently reduce IQ. Blood lead levels are measured in micrograms per deciliter, and levels once believed safe—65 µg/dL, then 25, then 15, then 10—are now known to cause serious damage. The EPA now says flatly that there is "no demonstrated safe concentration of lead in blood," and it turns out that even levels under 10 µg/dL can reduce IQ by as much as seven points. An estimated 2.5 percent of children nationwide have lead levels above 5 µg/dL.

 The Economist makes a similar case. In its new-year issue: "The World in 2013" the magazine published an obituary for lead, because 2013 marks the year a UN deadline will take effect demanding that all nations around the globe phase out mass consumer sales of leaded gasoline. What countries still have lead at the pumps? Take a look at a 2009 graphic:

The Economist lists the 2013 nations by name:

They are an interesting bunch: Afghanistan, Algeria, Iraq, Myanmar, North Korea, Sierra Leone, Yemen. None is a happy place. All are afflicted by violence, and three by long-running wars. Opponents of lead in petrol, or in anything else, might conclude that their case is closed. Lead’s pernicious presence lowers intelligence and increases aggression, typified by the urge to roar through dusty cities in heavily armed, pollution-spewing trucks.

In other words, there is good news ahead for some of the most dangerous places on earth... and if it comes, it will be thanks to science, regulation, and globalism.