Much like mines in the modern age, scholars have long assumed that ancient mining and metallurgy were highly toxic and dangerous, claiming the industry had a long-term, detrimental effect on the environment and nearby communities. But new research based out of what some consider King Solomon’s fabled copper mines is upending that hypothesis.
A new study of soil samples from two Timna-area mines in southern Israel, authored by Prof. Erez Ben-Yosef of Tel Aviv University and his team, has shown that metal pollution as a result of the ancient copper industry was minimal. Most of “the population in the past, and today, most probably did not suffer at all from any kind of health consequences” resulting from the mines, Ben-Yosef told The Times of Israel by phone.
The study, “Pre-Roman copper industry had no polluting impact on the global environment,” was published in the peer-reviewed Scientific Reports (Nature) in late November. Ben-Yosef, of TAU’s Department of Archaeology and Ancient Near Eastern Cultures, led the research team, which included Dr. Omri Yagel, Willy Ondricek, and Dr. Aaron Greener.
“The big deal is that we say most of these previous studies are wrong, [and] over-exaggerate the environmental impact” of ancient mining, he said.
In announcing the study this week, TAU said more diplomatically that the new research overturned “prevailing scientific beliefs” that copper mining in antiquity created significant pollution and showed that “the environmental pollution resulting from copper production at King Solomon’s Mines was minimal and spatially restricted, posing no threat to the region’s residents, either in antiquity or today.”
The Timna Valley is located roughly 20 kilometers (12.5 miles) north of the Gulf of Eilat in the southern part of the Arava Desert. Nestled between sheer cliffs, it has a natural ecosystem that forms part of the Saharo-Arabian Desert Belt. Timna Park, one of Israel’s largest, is a popular destination for hiking, camping and desert activities.
Since the 5th millennium BCE, but particularly during the Late Bronze and Iron Ages (13th to 9th centuries BCE), the area was the site of one of the most important copper production centers in antiquity and has long been associated with King Solomon.
Although the Bible does not specifically refer to the Timna mines, it does say that King David conquered the region and placed garrisons in the area, known at the time as Edom. His son King Solomon utilized immense quantities of copper for building the Jerusalem Temple, which was likely sourced in the Timna Valley.
Previous research at Timna has uncovered cloth scraps dated from 1,000 BCE, the time of King David, which had been colored purple with the dye of sea snails, and olive pits and other foodstuffs found at Timna have been dated to around the same period.
The “very intensive” study involved taking hundreds of soil samples from two major copper production sites in the Timna Valley, “one from the Iron Age and King Solomon’s era and another nearby that is about 1,500 years older,” the researchers said.
The study found that metal pollution levels at these sites, which because of the dry conditions are not very affected by runoff from regular rainfall, were “extremely low and confined to the locations of the ancient smelting furnaces,” and well within current US Environmental Protection Agency levels for safe industrial workspaces and residential areas, the university said.
Against the grain
The study results are “a kind of criticism towards the scientific community,” Ben-Yosef noted.
In the past, “any type of any elevated amount of lead or copper in the soil was published as ‘pollution.’ And it’s not the right way to do it because pollution means something that is harmful to the environment, for the plants, for the animals and for humans,” he said.
“We did the soil survey and we have great results, which show that only in the immediate vicinity of the furnace it was a little bit dangerous for specific individuals that were working at the furnaces themselves,” Ben-Yosef said.
That is not to say working in the mines wasn’t dangerous, he added, as miners had to contend with toxic gas pockets, heat, falling rocks and a myriad of other perils. But the study results do show that exposure to toxic amounts of metals that had leaked into the surrounding area as a result of the mining industry was likely not among them.
“Some of the studies in the past claimed that this region is toxic, even today, for people working and living in the Timna area and in the other side of the Araba in Jordan. There are also ancient copper mines there in Jordan, and there are some studies arguing that the current Bedouins suffer from this ancient pollution,” Ben-Yosef said.
Potential pollution from Timna was also a personal concern, Ben-Yosef said. “I’ve been working in Timna for the last 20 years, in the ancient copper mine. So this question was always in my mind, for my team and myself,” he said.
Human impact
Ancient pollution is “an interesting question, something that is related to the beginning of the Anthropocene. When did humans start to really impact the natural environment? The exploitation of natural resources, including metals, is of course a part of it,” Ben-Yosef explained.
But, “we see in Timna, that at least before the Roman period and probably even after the Roman period, these ancient copper industries were not that polluting,” he said.
A 1990s study examined ancient ice cores in Greenland and argued that traces of copper found there had traveled through the atmosphere from sites of early copper production in the Levant like Timna, but “we were able to show that this observation in Greenland was not repeated. It’s most probably a mistake,” Ben-Yosef said.
A series of studies in the Wadi Faynan area in Jordan in the 2000s, another site of ancient copper production, concluded that the mines there led to “widespread environmental contamination.” However, more recent studies have shown methodological flaws in these efforts and pointed to very low pollution levels in Faynan. This is a “similar picture” to Timna, the authors noted in the new paper.
Elevated levels of metals found in soil samples have been used to discover sites of ancient metallurgy — most recently in China. But that doesn’t mean those sites were polluted to dangerous levels, Ben-Yosef said.
A research project from 2022, also led by Ben-Yosef, showed an environmental impact of a different kind: the copper production at Timna necessitated a huge amount of trees and vegetation to be cut down for fuel, the researchers found, leading to a collapse of the copper industry there when the local fuel supply was finally depleted.
Roman period sees greater human impact
Copper production in the ancient world always involved lead, and this metal is the actual toxic pollutant, Ben-Yosef noted. The new research found that at Timna, lead residue was concentrated in the actual furnace area and in the slag, the rocklike residue produced as a byproduct of the process, and not dispersed in dangerous levels over a wide area.
Lead production “as an industry might have had a global impact starting with the Roman period,” when the use of lead became much more widespread, he said, but “other metal industries were not necessarily so harmful even during the Roman period and after.”
Even during the Roman period, the impact of metallurgy and mining on the landscape “was very minimal… and in modern times it’s huge. The scale is different and also the technology,” Ben-Yosef said, noting that modern copper production involves “aggressive” chemicals and solutions that easily can enter the water table.
The Industrial Revolution, usually considered as beginning in the mid-18th century CE, was “a major change in the relation between humans and the environment, and we know that metal industries are very toxic and polluting… but we should be very careful with projecting the current problems into the past,” he said.
Sue Surkes contributed to this report.
