Lead pollution likely dropped the average IQ in ancient Rome by 2.5 to 3 points, a study found. The research is based on an analysis of lead concentrations in ice cores extracted from Greenland.

Lead pollution in ancient Rome was so high that it dropped the population’s IQ by around 3 points, if not more. Elites were exposed to lead through water pipes, cooking pots, bath tubs ...

But hidden in this industrious age of antiquity was a poison that quietly shaped the fate of Rome ... evidence of lead’s toll ...