The Roman Empire had a thriving metallurgical industry that heavily used lead. It polluted everything around it and caused the IQ of Europeans of the time to drop by 2-3 points.
This is stated in a study published in the Proceedings of the National Academy of Sciences.
Researchers say that the massive expansion of mining and the processing of metal ores, in particular, led to a sharp increase in lead air pollution at the height of the empireʼs power, seriously damaging peopleʼs health and intelligence.
It is known that Roman doctors were aware of the dangers of lead poisoning, but the metal continued to be used for water pipes and pots, in medicines, cosmetics and toys. Lead was also added to wine because it was found to keep it longer.
To track the level of lead air pollution in Roman times, an international team of researchers analyzed ice cores drilled in the Arctic and learned the concentration of lead in the atmosphere from 500 BC to 600 AD.
Ice cores showed a sharp increase in lead pollution around 15 BC, after the heyday of the Roman Empire, and levels remained high until the empireʼs fall in 180 AD. Over half a million tons of lead entered the atmosphere during this period.
The researchers also found that, on average, blood lead levels in children during the heyday of the Roman Empire could have increased by 2.4 micrograms per deciliter, which lowered their IQ by 2.5 to 3 points.
By some estimates, at its peak, the Roman Empire had over 80 million people, meaning about a quarter of the worldʼs population could have been exposed to lead pollution.
“A 2.5-3 point IQ reduction may seem insignificant, but it was observed across the entire population and persisted for almost 180 years. I leave it to epidemiologists, ancient historians, and archaeologists to determine whether such pollution and its health effects were sufficient to change the course of history,” noted researcher Joseph McConnell.
- The Roman Empire was one of the most powerful and influential states in history, lasting from 27 BC to 476 AD. At its peak (1st–2nd century AD), the Roman Empire encompassed the territories of modern-day Europe, Africa, and Asia.
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