Archaeology News

Sunday 15th February 2015

The Conquistadors’ Role in Ancient Air Pollution

Researchers at The Ohio State University have found evidence of toxic air pollution produced during the Spanish conquest of the Inca Empire in Peru.

During the 16th century, the Spanish conquest resulted in widespread destruction of the Inca land and its people. However, recent findings suggest the introduction of a different silver mining method also created man-made air pollution which predates the industrial revolution by almost two centuries.

The evidence comes from the study of core samples taken in 2003 from the Quelccaya ice cap located in the Cordillera Oriental section of the Andes mountains of Peru. Researchers used a mass spectrometer* to measure the amount and type of certain chemicals in these samples including lead. From the late 1500’s, the ice began capturing much larger quantities of lead particles which indicates the rise in toxic air pollution.

In 1572 the Spanish introduced a new type of technology to the Inca to boost the production of silver mining. This involved grinding silver ore into a powder, which actually contained much more lead than silver. The powder was then mixed with mercury in a process called amalgamation. This new way of silver mining produced thick clouds of dust which rose over the Andes.

The location of mining process was in the mountaintop silver mines of Potosí, now located in Bolivia. It is understood that the wind carried the air pollution some 500 miles northwest to the Quelccaya ice cap, where it settled for for several hundreds of years.

The findings are the first evidence of widespread anthropogenic air pollution in South America, and provide yet another clue into the dark history of the Spanish conquest.

*The mass spectrometer is an instrument which can measure the masses and relative concentrations of atoms and molecules.