Scientists have recently discovered what could be considered as the world's first polluted river. As per the experts, the river had been contaminated about 7,000 years ago by Neolithic humans who may have been making copper metals from ores.
According to a report published in Deccan Herald, Professor Russell Adams from the University of Waterloo in Canada and colleagues found evidence of early pollution caused by the combustion of copper in the dry riverbed in the Wadi Faynan region of southern Jordan.
The researchers' findings gave information about a turning point in history when human started moving from making out of stones to making tools out of metal. The period, known as the Chalcolithic or Copper Age, is a transitional period between the late Neolithic or Stone Age and the beginning of the Bronze Age.
"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. "The technological innovation and the spread of the adoption and use of metals in society mark the beginning of the modern world," he added.
It was believed that people created copper during this time by mixing charcoal and the blue-green copper ore, which can be found in large quantities in the area in pottery vessels and heating the mixture over a fire.
Because the process was time-consuming and labor-intensive, it took thousands of years before copper became a central part of human societies. Times of India reported that many of the objects created in the earliest phase of copper production were primarily symbolic and fulfilled a social function within society. Getting rare and exotic items was a way that individuals attained prestige.
Meanwhile, as time passed, communities in the region grew larger and copper production expanded. People built mines, then large smelting furnaces and factories by about 2600 B.C.
"This region is home to the world's first industrial revolution. This really was the center of innovative technology," said Adams.
However, people paid a heavy price for the increased metal production. Slag, the waste product of smelting, remained. Researchers reported that it contained metals such as copper, lead, zinc, cadmium, even arsenic, mercury and thallium.
They also said that plants absorbed these metals, people and animals such as goats and sheep ate them, and so the contaminants bioaccumulated in the environment. Adams believed that the pollution from thousands of years of copper mining and production must have led to widespread health problems in ancient populations.
It is also important to note that experts named infertility, malformations and premature death as some of the harmful effects of the contamination. They also found high levels of copper and lead in human bones dating back to the Roman period.
Researchers are now trying to expand the analysis of the effects of this pollution to the Bronze Age, which began around 3200 B.C.