The ancient Romans developed concrete, aqueducts, and laid down the foundation for our current calendar system. However, according to research, they might have accomplished much more if their cognitive abilities hadn’t been impaired by lead poisoning.
Oxford University has determined that lead contamination led to a decrease of at least two to three IQ points for people across Europe.
“Reducing the average IQ by two to three points might not seem significant, but when applied to nearly all Europeans, it becomes quite substantial,” stated Nathan Chellman, who co-authored the study.
Lead is recognized for causing numerous health issues in humans, however, we decided to concentrate on cognitive decline since this is an impact that can be quantified.
Low-level lead exposure contributes to various negative health outcomes, particularly impacting cognitive development.
To determine the extent of lead presence in the atmosphere during this period,
Roman period
Researchers analyzed three ice core samples to determine pollution levels in the Arctic from 500 BC to 600 AD.
This period covers the emergence of the
Roman Republic
up until the decline of the Western Roman Empire, with an emphasis on the 200-year era known as the Pax Romana, a flourishing time span that extended from 27 BC to 180 AD.
The team particularly focused on analyzing lead isotopes, as these can indicate the origin of the metal, in this instance tracing it back to mining and smelting activities.
Much of the ancient lead contamination originated primarily from silver mining activities, during which lead-heavy minerals like galena were heated to retrieve the valuable metal.
For each ounce of silver extracted through this method, thousands of ounces of lead were generated—much of which ended up being emitted into the air. According to the research, the resultant contamination started as early as the Iron Age and peaked during the latter part of the 2nd century BCE, coinciding with the zenith of the Roman Republic.
It subsequently dropped dramatically during the 1st century BCE, amid the crisis period.
Roman Republic
, which increased around 15 BCE with the rise of the Roman Empire.
Lead contamination stayed at elevated levels until the onset of the Antonine Plague, spanning from around 165 to the 180s CE, significantly impacting the Roman Empire. Research indicates that over 500 kilotons of lead were emitted into the air throughout the peak period of approximately two centuries during the Roman Empire’s existence.
Even though ice core data indicates that Arctic lead contamination was as much as 40 times greater at the peak around the early 1970s, the findings reveal that human activities have impacted public health for millennia, according to the scientists involved in the study.
As lead contamination has decreased over the past three decades, it has increasingly become clear to health scientists and medical professionals exactly how detrimental lead can be for human growth.
“This marks the first study to derive atmospheric pollution levels from an ice core record and subsequently evaluate their impact on humans,” stated Dr. Joe McConnell, research professor of hydrology and the principal author of the study.
The notion that we can achieve this from 2,000 years ago is quite innovative and thrilling.
The study was published in the Proceedings of the National Academy of Sciences PNAS.
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