The findings of the research, published in Science of the Total Environment this week, say that early pollution in the now-dry river in the Wadi Faynan region of southern Jordan was caused by the combustion of copper. The period was a turning point in history when people shifted from making tools from stones to making tools from metal. This period, called the Chalcolithic or Copper Age, is a transitional period between the Stone Age and the beginning of the Bronze Age.
Anthropology Professor of Waterloo University in Canada Russell Adams and his colleagues, who made the discovery, based on intense copper pollution and remnants of fires in the area, suggest that ancient inhabitants made copper by combining charcoal and ore in pottery crucibles and heating it over a fire.
"These populations were experimenting with fire, experimenting with pottery and experimenting with copper ores, and all three of these components are part of the early production of copper metals from ores," said Adams.
At the beginning, the process was time-consuming and labour-intensive and it took thousands of years for copper to become a central part of human society. At that time, "What they [metallurgists] were able to do must have seemed magical, since they took rock and turned it into a really highly prized, beautiful, shiny piece of metal," Adams said.
Over time, the area became more populated, leading to the expansion of copper production. Mines, large smelting furnaces and the first factories were built by about 2,600 BC.
As Adams put it, "This region is home to the world's first industrial revolution. This was the Silicon Valley of the age. It really was the centre of innovative technology."
The researchers plan to continue their study and extend it to the effects of pollution in the Bronze Age.
Nowadays, water pollution is an extremely acute global ecological problem.