Using Arctic ice core samples, researchers estimate silver mining and smelting released enough lead during the Pax Romana to cause a 2.5- to 3-point drop in IQ

The new research adds context to a long-standing debate about the role lead pollution and poisoning may have played in the collapse of the Roman Empire. Some historians have argued that Roman elites and emperors who purportedly displayed odd,

Using modern evidence of lead pollution and its health effects, the international team calculates that lead exposure in the Roman golden age could have caused a population-wide drop in IQ of about 2.5 to 3 points per person. And that goes for most of the Roman Empire, including its provinces of Gaul, northwestern Africa, Iberia, and Britannia.