Although I acknowledge that lead is nasty stuff, something about this issue bothers me. According to some studies, increasing exposure to lead at low levels (

Although I acknowledge that lead is nasty stuff, something about this issue bothers me. According to some studies, increasing exposure to lead at low levels (1-10 micrograms/dl) shaves 4-7 points off IQ scores[1]. Yet, as population blood lead levels have plunged in recent years, there haven't been proportionately massive gains in IQ in the population. Indeed, the Flynn effect may have stalled in recent years[2]. This either means that there are confounders or some other effect is in place. But I'm no expert, and I'd value the input of someone better informed. [1] http://www.nejm.org/doi/full/10.1056/NEJMoa022848 http://www.nejm.org/doi/full/10.1056/NEJMoa022848 [2] http://en.wikipedia.org/wiki/Flynn_effect#Possible_end_of_progression http://en.wikipedia.org/wiki/Flynn_effect#Possible_end_of_pr...