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Found: A River Humans Started Polluting 7,000 Years Ago

Playing with metal and fire led to unusual concentrations of copper on a streambank.

Copper wire on fire.
Copper wire on fire. Danielle Crowe/Public domain

In the Wadi Faynan region of southern Jordan, thousands of years ago, people were starting to play with metal. In this area, there’s one of the earliest documented centers of metal extraction in the world, which dates back to the fourth millennium B.C. A team of researchers wondered, though, what happened before that—before they were purposefully extracting it from the earth, how did humans explore the possibilities of metal?

In their exploration, they found an unusual site, a place on the banks of a now-dry waterway that showed evidence of copper contamination. Approximately 7,000 years ago, the researchers hypothesize in their paper, published in the journal Science of the Total Environment, a group of people gathered copper ores, brought them a few kilometers to the banks of a stream, and put those metals into very hot fires.

They did this often enough that they created unusually high concentrations of copper in this one spot —which the research suggest could be considered “the first polluted river.”

Why were people throwing copper ore into the fire? It’s not clear, of course, at this distance in time. It’s likely that they weren’t yet purposefully smelting the copper into shapes, but they might have been using it for “fun, enquiry, ritual and/or spiritual reasons,” the researchers write. As they point out, the combination of metal and fire would have created “multi-colored flames,” and it’s easy to imagine the pull of a dancing rainbow fire on the banks of a small stream.

Eventually, this sort of ritual and flame might have led to the creation of metallurgy. What we know most clearly is the in this one spot, there’s a strange concentration of copper, and it can’t be attributed to natural causes. Humans did this, and it’s one of the earliest examples we have of the permanent waste our activities leave behind.