Lead poisoning caused lower IQs in Ancient Rome

While Ancient Rome was flourishing thousands of years ago, something ominous was in the air – literally.

Lead pollution during the Roman Empire grew to a high enough level that it dropped the population's collective IQ, potentially aiding in the empire’s fall, according to a recent peer-reviewed study.

By the numbers

The research actually started far from Rome, in the Arctic temperatures of Greenland and Russia. Scientists located three ice cores with lead levels dated between 500 BCE–600 CE, roughly the same span as the rise and fall of the Roman Empire.

• After analyzing the ice cores, the researchers concluded that Roman silver mining operations emitted an estimated 3,300-4,600 tons of lead into the atmosphere each year – the earliest known example of widespread industrial pollution.
• As a result, the average Roman had enough lead in their blood to cause a general IQ decline of ~3 points across the entire population.

📝 Bottom line: While there’s no definitive answer on the Roman Empire’s fall, the study's authors say their findings show “lead was one of many risk factors that could have contributed to [its] decline.”