12,000-year-old Roman burial site sparks concern over growing lead pollution

As one of the most widely used heavy metals, lead has had a complicated relationship with human history due to its effects on human health and the environment. A 12,000-year-old burial site in Italy confirmed just how strained this relationship was – researchers found that with every increase in lead use, there was a corresponding increase in lead pollution that was found in the remains of 132 people at the place.

In a study published last week in Environmental science and technologyresearchers have confirmed that the increase in lead production in history is linked to corresponding increases in lead pollution in humans.

“This observation raises concerns that the projected increase in the production of lead and other metals could soon affect human health,” the document said.

“Put simply: the more lead we produce, the more likely people are to absorb it into their bodies. This has a highly toxic effect,” said Yigal Erels, a geologist from the Hebrew University of Jerusalem in Israel and lead author. of the study, in a report.

The study was able to determine the link by directly observing bone lead concentration at the burial site to study the evolution of lead exposure in humans since its discovery and widespread production about 5,000 years old.

The calculation of the lead concentration was made using the “lead to calcium ratio” – since lead is mainly stored in bones and teeth, and calcium is a key component. The researchers also studied the presence of 20 other elements and found that there were no significant changes in zinc, potassium and others, showing that the increase in lead cannot be explained by factors. natural biological processes.

With the production of coins around 2,500 years ago, lead production reached its peak during the Roman Empire. Previous studies of ice glaciers and lake sediment samples have confirmed that its spread among local populations increased at this time. While the lead to calcium ratio in human remains was high when the Romans first started using it, it was after 2,500 years that this ratio increased sharply.

Moreover, while Previous search found a four-fold increase in lead production from the dawn of metallurgy to the height of the Roman Empire, the current study has shown that the corresponding lead concentration found in human bones during this period was multiplied by 4,000.

More worryingly, even people who were not involved in local mining or smelting showed lead levels in their remains.

Indeed, the Romans used lead so much that some theories suggest that lead was responsible for the fall of the ancient Roman empire.

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Lead production then fell in the Middle Ages. However, the pace quickened 1000 years ago with the increase in silver mining, where lead was obtained as a by-product. It was only in the last 250 years that lead began to be mined exclusively for its own use, the researchers note – and the new study shows that these global production patterns are reflected in analysis of bones from the site.

With these findings, researchers are concerned about a potential increase in lead addiction when switching to alternative energy sources, and the impact this would have on humans in vulnerable situations. Scientists estimate that to keep the global temperature increase to less than 2 degrees Celsius instead of 6 degrees by 2050, there would be a 1,200% increase in demand for lead, nickel and cobalt for energy storage technologies

“This raises concern that the current increasing use of several toxic metals (including Pb) in electronic devices and the transition to low-carbon energy production will soon result in elevated concentrations of these metals. in humans, primarily in those who are unlucky enough to live in regulated and monitored regions,” the study notes.

The researchers cited various other studies demonstrating the effects of lead pollution in people, especially children. Pollution pathways include exposure sources as diverse as air, food and industrial lead. In addition, poorer living conditions and socio-economic conditions are factors of lead concentration in children, which has adverse effects on their neurological development, learning and behavior.

According to World Health Organization (WHO), lead poisoning affects almost all organ systems and there is no level of exposure that is not accompanied by adverse health effects. It is also one of the 10 chemicals identified by the WHO as a major public health problem.

Given these effects, the researchers argue that “increased use of metals should go hand in hand with increased industrial hygiene, maximum recycling of metals, and consideration of environmental and toxicological aspects in the selection of metals for industrial use. “.

David C. Barham