A new study has revealed that environmental lead pollution caused by humans was present even as early as 8000 years ago.
"Humanity's environmental legacy spans thousands of years, back to times traditionally associated with hunter-gatherers. Our records indicate that the influence of early Native Americans on the environment can be detected using lake sediments," said David Pompeani, lead author of the research paper and a PhD candidate in Pitt's Department of Geology and Planetary Science.
"These findings have important implications for interpreting both the archeological record and environmental history of the upper Great Lakes," Pompeani said.
The team examined Michigan's Keweenaw Peninsula as this place is the largest source of pure native copper in North America. They looked at the extent and location of ancient copper mining pollution. Concentration of lead, iron, magnesium, titanium, and organic matter in the collected sediment cores was analyzed which was preserved from 1000s of year ago.
"These data suggest that measurable levels of lead were emitted by preagricultural societies mining copper on Keweenaw Peninsula starting as early as 8,000 years ago. Collectively, these records have confirmed, for the first time that prehistoric pollution from the Michigan Copper Districts can be detected in the sediments found in nearby lakes."