A new study by Tel Aviv University researchers challenges long-standing assumptions about the environmental and health impacts of King Solomon’s copper mines in southern Israel’s Timna Valley. It suggests ancient copper production posed minimal risks to workers and nearby residents.
Geochemical surveys at sites dating back to the 10th century BCE—during the reigns of the biblical monarchs David and Solomon—revealed that pollution from copper production was minimal, highly localized and posed no danger to the region’s inhabitants, past or present. A review of prior research also found no evidence linking ancient copper mining to global pollution.
The study, led by professor Erez Ben-Yosef, Omri Yagel, Willy Ondricek, and Aaron Greener of Tel Aviv University’s Jacob M. Alkow Department of Archaeology and Ancient Near Eastern Cultures, was published in Scientific Reports.
“We investigated two major copper production sites in the Timna Valley, one from the Iron Age and King Solomon’s era and another roughly 1,500 years older,” said Ben-Yosef.
“Our extensive study included hundreds of soil samples, analyzed to create high-resolution maps of heavy-metal distribution in the region. We found pollution levels were extremely low and restricted to the vicinity of ancient smelting furnaces. For example, lead concentrations—considered a key pollutant in metal industries—drop to below 200 parts per million just a few meters from the furnaces. By comparison, the U.S. Environmental Protection Agency considers industrial areas safe for workers at up to 1,200 parts per million and residential areas safe for children at 200 parts per million.”
The study also refutes claims made in research from the 1990s suggesting that ancient copper production caused widespread pollution.
“Our findings show this is not true,” the researchers explained. “Pollution at Timna was confined to those working directly at the furnaces, who may have inhaled toxic fumes, but the surrounding soil is safe. Additionally, the metals are trapped in slag and other industrial waste, preventing them from leaching into the environment or affecting plants and humans.”
The researchers noted that their findings align with recent studies of Wadi Faynan in Jordan, another ancient copper production site. Timna and Wadi Faynan, undisturbed by modern mining and located in arid climates, have preserved localized heavy metals without broader environmental contamination.
In addition to their geochemical surveys, the researchers reviewed existing literature, challenging the notion that ancient copper mining caused global pollution.
“In the 1990s, there was a trend to portray ancient copper production as the first example of industrial pollution,” said Yagel. “These claims gained attention but projected modern pollution concerns onto the past. The term ‘pollution’ was often used too broadly, leading to the mistaken belief that ancient metal industries were inherently harmful. While large-scale lead production eventually caused global pollution, early copper production did not.”
Yagel also addressed a 1990s claim that copper traces in Greenland ice cores originated from ancient sites like Timna. “No subsequent research has corroborated this claim,” he said. “As we confront today’s environmental crises, it’s important not to overstate the environmental impact of ancient activities. Localized slag waste is not the same as regional or global pollution.”
