It was announced by scientists that traces of air pollution from 16th century conquistadors were found in ice from the Peruvian Andes. The mining conquistadors left behind an impressive amount of pollution that can now be analyzed to learn more about those people.
Even though the imprint of smog, which was found to be very metal-rich, was found in Peru, scientists are certain that the pollution originated from what is now Bolivia, hundreds of miles away, at the mines in Potosí.
Situated at an altitude of about 13,120 feet (4 km) Potosí is a UNESCO World Heritage Site thanks to its very rich industrial history. Before the Spanish conquistadors, the Inca people had been digging up and refining silver from this location for hundreds for years.
During the colonial period though, mining in Potosí flourished and it became the number one source of silver in the world.
In the 17th century around 13,000 indigenous people were forced to work the mines, while around 150,000 colonists set up permanent living in Potosí.
Air pollution from 16th century conquistadors happened because the Spanish introduced a new method of speeding up silver production, called amalgamation that required grinding rich-silver ore into a powder and then mixing it with mercury.
During mining, large clouds filled with lead were released into the atmosphere and pollution was taken northwest, 500 miles (800 km) where it settled in southern Peru, in the Quelccaya Ice Cap.
A long ice core was pulled from the ice cap in 2003 to study the climatic changes that took place in South America during the last two millennia. While the soot-stained ice cannot be observed with the naked eye, chemical analysis showed that Quelccaya started catching large quantities of metal (lead in particular) and that around the early 1800s, the pollution stopped. It was around that time, that the Latin American Wars of Independence took place and the mining industry suffered.
Even though the pollution in the Quelccaya Ice Cap showed that the area had some of the biggest pollution in the world at that time, it is still several times lower that the present level of pollution.
Image Source: Ibtimess