The copper production associated with the mines of the biblical King Solomon may not have harmed the workers involved – nor does it pose a threat to local residents today.

That’s the conclusion of a new study that refutes a decades-old hypothesis about the harmfulness of ancient smelting practices.

“We show that this is not true,” said the paper’s author and archaeologist Professor Erez Ben-Yosef of Tel Aviv University, adding that the pollution is highly localized.

“It is likely that only those working directly in the furnace suffered from inhaling toxic fumes, while the ground just a short distance away is completely safe.”

In their study, the researchers analyzed two major copper production sites in Israel’s Timna Valley, one from the Iron Age – and King Solomon’s era – and another nearby that is roughly 1,500 years older.

At both sites, the team collected hundreds of soil samples for chemical analysis, the results of which allowed them to create high-resolution maps of the local presence of heavy metals.

They found that pollution levels around copper mining sites in the Timna Valley were extremely low – and concentrated only where old smelting furnaces had once been.

“For example, the concentration of lead – a primary pollutant in the metal industry – drops to less than 200 parts per million just a few meters from the furnace,” said Ben-Yosef.

“By comparison, the US Environmental Protection Agency defines industrial areas as safe for workers at 1,200 parts per million and residential areas as safe for children at 200 parts per million.”

According to Ben-Yosef, heavy metals are also effectively captured in the form of slag – stony waste from furnaces – and other industrial waste, meaning they are unable to cause harm by leaching into the local environment.

The findings match those previously reported from the Wadi Faynan region of Jordan. In this study – led from the Hebrew University – the team studied the skeletons of 36 Iron Age individuals who lived at the Faynan mining site. The team found that only three of the skeletons showed any signs of contamination.

Together, the studies challenge the long-held belief that the ancient copper industry generated widespread copper pollution — one that the team says lacks solid supporting evidence.

“In the 1990s, there was a trend that presented old copper production as the first case of industrial pollution,” said paper co-author and Tel Aviv University archaeologist Omri Yagel.

“Such statements grab headlines and attract research grants, but they unnecessarily project modern pollution problems into the past.”

In addition, Yagel notes, past research has tended to use the word “pollution” to describe any trace of ancient metallurgy—leading to confusion about the extent of the impact of such activities.

In fact, the archaeologist explains that even when metal production became an extensive and integral part of civilization, it was still only toxic lead—and not so much other metals—that resulted in widespread pollution.

“As researchers facing the serious environmental challenges of our time, such as climate change, we often tend to look for similar problems in the past or to assume that environmental damage is an inevitable consequence of human activity since the agricultural revolution,” added Yagel. .

However, he added: “We need to be careful. While we might label a few bits of slag on the ground as ‘pollution’, we should not confuse this localized waste with regional or global environmental pollution.”

Link

Yagel, O., Greener, A., Ondříček, W., & Ben-Yosef, E. (2024). The pre-Roman copper industry had no polluting impact on the global environment. Scientific reports, 14(1), 29675. https://doi.org/10.1038/s41598-024-80939-5