Lead, Manganese, and Methylmercury as Risk Factors for Neurobehavioral Impairment in Advanced Age

Figure 1

Showing the consequences of a shift in the population IQ of 5 points (5%) in a population of 100 million. In most US school districts, an IQ of 70 or lower (2 SDs below the mean) mandates remedial action. (Based on Weiss [3]).