Modern pollution exists on a global-industrial scale, but a site in Jordan might be where it all began about 7,000 years ago, before the dawn of the Bronze Age, reports Phys.org.

Researchers have uncovered evidence of what might have been history's first polluted river, a now-dry riverbed in the Wadi Faynan region of southern Jordan that appears to have flowed with slag, a waste product from smelting. The site dates to a period known as the Chalcolithic, or Copper Age, a time of transition 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," explained Russell Adams from the Department of Anthropology at the University of Waterloo. "The technological innovation and the spread of the adoption and use of metals in society mark the beginning of the modern world."

Unfortunately, the beginning of the modern world also meant pollution. As these people began experimenting with the smelting of copper, they inadvertently dumped their waste — which may have also included metals such as lead, zinc, cadmium,and even arsenic, mercury and thallium — into rivers.

This could have caused widespread destruction to local ecosystems. Plants along the river would have absorbed these metals, which would have bioaccumulated as animals ate those plants. As people ate the animals, it would probably have led to widespread health problems, from infertility to birth defects to premature deaths. The aftermath would have offered a grim glimpse of what was to come — the cost of advancing civilization technologically.

The Faynan region would eventually become a focal point for Bronze Age smelting. Large smelting furnaces and factories were being built by around 2600 BC.

"This region is home to the world's first industrial revolution," said Adams. "This really was the center of innovative technology."