Air Pollution from the Roman Empire May Have Reduced Europe’s IQ

At its height, the Roman Empire’s influence spanned across land, sea, and even the skies. During the peak of Roman imperialism, air pollution became so widespread that researchers now believe it may have caused significant neurological damage across much of Europe, including what is now Great Britain.

Ice-core data from the Arctic reveals that atmospheric levels of toxic lead surged between 100 BCE and 200 CE, coinciding with the Roman Empire’s unprecedented mining and metal smelting activities.

Researchers estimate that a child born within the Roman Empire during this period would have had, on average, three times more lead in their blood than children in the US today.

The Cognitive Cost of Lead Exposure in Ancient Rome

By examining modern data on lead pollution and its health impacts, an international team of researchers calculates that lead exposure during the Roman Empire’s golden age may have caused a decline in average IQ by about 2.5 to 3 points per person. This would have affected much of the Roman Empire, including provinces like Gaul, northwestern Africa, Iberia, and Britannia.

“An IQ reduction of 2 to 3 points may not seem significant, but when applied to nearly the entire European population, it becomes substantial,” says Nathan Chellman, a snow and ice hydrologist at the Desert Research Institute in the US.

These figures only account for lead pollution in the air; lead pipes and vessels also directly exposed elite Romans and urban populations to toxic particles.

The research team, including climatologists and epidemiologists from institutions in Denmark, the UK, the US, Canada, Austria, and Switzerland, explains that all Europeans, along with their livestock and agricultural fields, were exposed to continuous background lead pollution for centuries due to the large-scale mining and processing of lead/silver ores, which were vital to the Greek and Roman economies.

“This ongoing lead pollution in the air and soil may have been the primary source of exposure for rural, non-elite populations.”

There is no safe level of lead in the blood or body, but higher concentrations lead to more severe consequences.

Epidemiological studies today show that blood lead levels as low as 3.5 µg/dl in children are associated with reduced intelligence and learning difficulties later in life, often measured by IQ tests.

The Enduring Impact of Lead Pollution in the US

In the US, lead pollution is sometimes called the “longest-running epidemic” in the country. Since the 1940s, experts estimate that lead exposure has decreased the IQ of half the population, largely due to the burning of fossil fuels.

Fortunately, lead exposure has drastically decreased over the past 40 years. With restrictions on leaded gasoline and other lead-based products, children in the US now have an average blood lead level of about 0.6 to 0.8 µg/dl.

During Roman times, children likely had an average blood lead level of 3.4 µg/dl, according to the current study’s models. As this is an average, many children likely had lead concentrations that posed a significant risk of neurological damage.

These findings align with previous ice-core studies, which have detected a surge in atmospheric lead during the height of the Roman Empire, as well as archaeological discoveries showing high levels of lead in the teeth of many Roman children.

“This is the first study to take a pollution record from an ice core, reverse-engineer it to estimate atmospheric pollution levels, and then assess the impacts on human health,” says Joe McConnell, hydrologist and lead author of the study.

Read the original article on: Science Alert

Read more: Trees in Los Angeles are Now an Unexpected Air Pollution Source