Exposure to the toxic metal resulted in the average person’s intelligence quotient falling up to 3 points, according to scientists
Widespread lead pollution in the Roman Empire may have caused cognitive decline across Europe that lasted nearly two centuries, a study has found.
The intelligence quotient (IQ) of an average resident of the ancient civilization is likely to have fallen by 2.5 to 3 points as a result of exposure to the toxic metal, according to the paper, published in the Proceedings of the National Academy of Sciences on Monday.
Scientists, who studied chemicals contained in ice cores extracted in Greenland, said they found that lead pollution in the Roman Empire rose sharply after 15 BC and remained high until the decline of the Pax Romana, a stretch of peace and prosperity that ended in AD180.
“It is amazing that we were able to quantify atmospheric air pollution over Europe nearly 2,000 years ago and assess potential health impacts on the ancient Roman civilization,” the lead author of the paper, Joseph McConnell, a climate and environmental scientist at the Desert Research Institute, stated.
The findings are “pretty profound” because they demonstrate that “anthropogenic emissions from industrial activities have resulted in widespread damage to human health for over two millennia,” he said.
The Roman Empire – which at its peak covered the entire Mediterranean region including North Africa, along with Western Europe and parts of the Middle East – was mining and smelting large quantities of silver and lead “for their coinage, for their economy” and as a result ,large amounts of toxic metal attached itself to particles of dust in the atmosphere, the scientist explained.
“A 2.5- to 3-point reduction in IQ may not sound like much but it was across the entire population and would have persisted for the nearly 180 years of the Pax Romana,” McConnell concluded.
The study only measured air pollution, but Romans were exposed to lead through other sources, including lead plumbing and kitchenware.
Scientists have long debated whether the wide use of the toxic metal played a role in the downfall of the Roman Empire.
“I leave it to epidemiologists, ancient historians, and archaeologists to determine if the levels of background atmospheric lead pollution and health impacts we have identified… were sufficient to change history,” McConnell said.
