Lead pollution weighed on IQ in the Roman era

Jan. 7 () –

Records of atmospheric pollution preserved in Arctic ice have made it possible to identify periods of lead pollution in the Roman Empire and How it could have affected the population.

Lead exposure is responsible for a variety of human health impacts, including Relatively low levels affect children’s cognitive development.

A study of Desert Research Institutepublished in Proceedings of the National Academy of Sciencesexamined three ice core records to identify levels of lead contamination in the Arctic between 500 BC and 500 BC. C. and 600 AD. C. This era covers the rise of the Roman Republic until the fall of the Roman Empire, and The study focuses on the roughly 200-year heyday of the Empire called Pax Romana.

The lead isotopes allowed the research team to identify mining and smelting operations across Europe as the likely source of contamination during this period. Advanced computer modeling of atmospheric movement produced maps of air lead pollution levels across Europe. Combined with research linking lead exposure to cognitive decline, the research team also identified probable reductions in IQ (intelligence quotient) levels of at least 2 to 3 points among the European population.

MILLENNIARY ICE LAYERS

“This is the first study to take a pollution record from an ice core and invert it to obtain atmospheric concentrations of pollution and then evaluate human impacts,” he says. in a statement Joe McConnell, research professor of hydrology at DRI and lead author of the study. “The idea that we could do this 2,000 years ago is quite novel and exciting.”

The McConnell Ice Core Laboratory at DRI has spent decades examining ice cores from places like Greenland and Antarctica, where ice sheets have accumulated for millennia.

Using huge drills, they painstakingly mine columns of ice up to 11,000 feet (3,400 meters) long, reaching depths farther in Earth’s history with every inch. McConnell’s team creates accurate chronologies using records of well-dated volcanic eruptions, that seal the ice record like postcards from the past.

Gas bubbles trapped in the ice offer information about the atmosphere of bygone eras, while contaminants such as lead can be used to interpret mining and industrial activity.

McConnell began developing methods to create highly detailed lead records in ice more than twenty years ago, when applied to more recent history.

When archaeologists and historians learned of this work, they approached it in hopes of applying these new techniques to the Roman period, seeking answers to lingering historical questions.

“The resulting research changed our understanding of the era by finding precise links between records of lead contamination and historical events such as population declines associated with plagues and periodic pandemics,” adds co-author and ancient historian Andrew Wilson of the University of Oxford.

Lead contamination in ancient times largely originated from silver mining, whereby the lead-rich mineral galena was smelted to extract silver. For every ounce of silver obtained, this process produced thousands of ounces of lead, much of which was released into the atmosphere.

“A reduction in IQ of 2 to 3 points does not seem like much, but when applied to virtually the entire European population, it is a very important thing,” Wilson added.

The study found that air lead pollution began during the Iron Age and It reached a peak at the end of the 2nd century BC. C. at the height of the Roman Republic. It then declined dramatically during the 1st century BC. C., during the crisis of the Roman Republic, before increasing around the year 15 BC. C., after the rise of the Roman Empire.

Lead contamination remained high until the Antonine plague, between 165 and 180 AD. C., which seriously affected the Roman Empire. It was not until the Early Middle Ages, at the beginning of the second millennium AD. C., when lead pollution in the Arctic exceeded the high sustained levels of the Roman Empire. According to the research, During the nearly 200-year heyday of the Roman Empire, more than 500 kilotons of lead were released into the atmosphere.