Quirks & Quarks

Spanish Conquistadors Brought Air Pollution

A glacier in the Peruvian Andes preserves a record of aerosol lead pollution from Spanish silver smelting in the 1500s.
The Quelccaya ice dome in the Peruvian Andes. (P. Gabrielli/Ohio State University)
When the Spanish invaded Central and South America in the 16th century they brought modern weapons, European diseases, and air pollution. 

Dr. Colin Cooke, a Water Quality Scientist at the Alberta Environmental Monitoring, Evaluation and Reporting Agency in Edmonton, and his colleagues, investigated ice cores extracted from a glacier in the Peruvian Andes that preserves a record of annual deposits dating back thousands of years. 

In it they found a spike in levels of several toxic metals, including lead and antimony, dating to the 1500s when the Spanish were intensively smelting silver using polluting open-air techniques.  They also found low levels of bismuth dating to the earlier Incan period, suggesting that air pollution in South America pre-dates the industrial revolution by centuries.

Related Links

- Paper in PNAS
- Ohio State University release
Science news article

Smithsonian.com article