The Roman Empire’s use of lead had the effect of lowering IQ levels across Europe, a study shows. Researchers describe how ice cores revealed a sharp increase in lead pollution around 15 BC.
Roman lead faucets and pipes. PHOTO wikiwand
Widespread use of lead caused an estimated drop in IQ for nearly 180 years during the Pax Romana (Latin for “Roman Peace” a period of about 200 years of relative stability within the Roman Empire that beginning with the reign of Augustus in 27 BC and ending in 180 AD with the death of Marcus Aurelius) according to The Guardian which reported on the results of the study.
The new study reveals widespread cognitive decline across Europe, due to the large amounts of polluting lead produced by the empire’s booming metal industry.
“Widespread damage to human health for over two millennia”
According to the researchers, the massive expansion of mining and metal ore processing, in particular, caused lead pollution in the air to increase during the empire’s peak period, leading to an estimated 2 to 3 point drop in IQ throughout the country.
“It is amazing that we have been able to quantify atmospheric air pollution in Europe nearly 2,000 years ago and assess the potential health impact of the ancient Roman civilization. Our findings demonstrate that anthropogenic emissions from industrial activities have resulted in widespread damage to human health for over two millennia, which is pretty profound in my view“, said Dr. Joseph McConnell of the Desert Research Institute in Nevada.
Although Roman physicians were aware of the dangers of lead poisoning, the metal was widely used for water pipes and cooking pots and was found in medicines, cosmetics and toys. Furthermore, after the Romans discovered that syrups containing lead helped to preserve and sweeten wine, the metal came to be ingested on purpose.
In addition, the population would have inhaled lead from the air produced by the empire’s vast mines and smelting operations, the metal being a byproduct of silver and gold refining.
To track levels of lead pollution in the air throughout the Roman era, McConnell and an international team of researchers analyzed ice samples taken from the Arctic. The samples provided a chronology of atmospheric lead concentrations from 500 BC. until 600 AD
The researchers described in the Proceedings of the National Academy of Sciences how ice cores revealed a spike in lead pollution around 15 BC. after the rise of the Roman Empire. And the levels remained high until the decline of the Pax Romana, which ended in AD 180.
The researchers found that, on average, the blood lead levels of children at the height of the Roman Empire could have increased by 2.4 micrograms per deciliter, reducing their IQ by 2.5 to 3 points.
The Roman Empire had more than 80 million people at its height, meaning that about a quarter of the world’s population could have been exposed to lead pollution from mining and smelting.
Researchers even question whether the effects of lead poisoning (which can be very serious) contributed to the fall of the empire.
“I leave it to epidemiologists, ancient historians, and archaeologists to determine whether the levels of lead air pollution and health impacts we have identified … were sufficient to change historyMcConnell said.
Lead pollution today
While lead air pollution declined after the Roman Empire, it increased again in the High Middle Ages and increased in the 20th century with the Industrial Revolution and the burning of fossil fuels, including leaded vehicle fuels. A 2021 study by the US Centers for Disease Control and Prevention found that blood lead levels in children aged one to five fell from 15.2 to 0.83 micrograms per deciliter between the late 1970s and 2016, with the ban on leaded fuels, writes The Guardian.
