LEAD AND IQ….Any of you who think that IQ is merely the reification of culturally approved behavioral norms will probably want to read no further, but for the rest of us this front page LA Times story has interesting news:

Blood levels of lead below current federal and international guidelines of 10 micrograms per deciliter produce a surprisingly large drop in IQ of up to 7.4 points, a U.S. team reports in today’s New England Journal of Medicine.

The researchers found that levels as low as 1 m/d cause most of the IQ drop, and that 10% of all children in the U.S. have levels above 5 m/d. There are about 60 million children in the United States today, so if these findings are correct it means that correcting this problem has the potential to result in an increase of 7.4 IQ points in over 6 million kids.

It’s hard to overstate the importance of this. A difference of 7.4 IQ points is a lot, especially when you start getting to the lower end of the IQ scale (say, an IQ of 83 compared to an IQ of 90), and the article goes on to quote a 1991 study showing that “lead abatement in old houses would cost about $32 billion, but would bring benefits in such areas as special education of more than $60 billion.”

I usually take these kinds of statements with a grain of salt, but in this case the benefits might even be understated. Not only does special ed cost a ton of money, but disruptive kids who are mainstreamed into normal classrooms ? many of them with low IQs in addition to other behavioral problems ? cause enormous problems for everyone else in the class. That’s a cost that’s hard to quantify.

If it turns out that this problem really could be solved for $32 billion, it would be about the best use of $32 billion you could possibly think of. Something to think about for a president who promised to leave no child behind.