Spanish Colonialism’s Environmental Legacy, Part One: Origins

Editor’s Note: This is the first of three guest posts by NC State history lecturer Nicholas Robins, an expert on the environmental history of South America and author of “Mercury, Mining and Empire: The Human and Ecological Cost of Colonial Silver Mining in the Andes.” Robins is also founder and president of the Environmental Health Council, which he launched as a result of his research on the book.

The mining cities of Huancavelica, Peru, and Potosi, Bolivia, once the pride of the Spanish empire, are now among the most mercury-contaminated urban areas in the world. We are only now beginning to understand the impact that the quicksilver-laced soils of these cities has on their populations today. But to truly grasp the problem, you need to understand how they got this way.

Although the Spanish conquistadors who came to the Americas sought gold, they found silver in much greater abundance. Not only would many make, and lose, their fortunes in its refining, but Latin American silver production would play a key role in forming today’s modern, global, economy. The refining of rich surface silver-containing ores through smelting was fairly straightforward, but such deposits were quickly depleted. As miners dug deeper, encountering greater expense and often the water table, they found lesser quality ores which were not suitable for smelting. In the case of the fabled city of Potosi, in present day Bolivia, the rich silver veins which were discovered in 1545 had been largely exhausted by the early 1560s. Miners’ optimism and opulence was quickly washed away by a rising tide of economic decline and despair.

What saved Potosi, and would transform the global economy while eviscerating indigenous communities, was not silver, but mercury. The introduction of the mercury amalgamation process in the Andes in the early 1570s allowed citizens of Potosi (or Potosinos), and other silver miners, to refine less rich ores, and breathe new life into their cities. With that new life, however, came illness and death, especially to the tens of thousands of draft laborers who were forced to labor in Potosi’s mines and mills under the mita system for forced labor.

Apart from Indian labor, the other critical component of the new economy, literally, was mercury. In the 1560s, the Spanish had uncovered one of the world’s largest deposits of cinnabar, from which mercury is refined, in the Santa Barbara Hill just outside of what is now the city of Huancavelica, Peru. With the adoption of the amalgamation process in Peru, Viceroy Francisco Toledo lost no time in asserting a royal monopoly on the production and sale of mercury, converting former cinnabar mine owners into crown contractors. Like miners in Potosi, they also benefitted from the mita system, thus avoiding many labor costs.

With these components in place, the Andean amalgamation economy took off. While much silver made its way to Spain, this was usually only a brief stop on a much longer journey. Whether to pay sovereign debt or as a result of commerce, this unprecedented influx of silver soon found its way to other European countries, and then was traded onward through the bazaars of Constantinople, to Persia, India, and ultimately, China. No small amount also was traded directly with China from the Americas. Although often debased, battered and broken, the Spanish “pieces of eight” had become a near universal currency by 1600, and would remain so for years to come. Exchanged and invested, it pried open new trade routes, fostered the industrial revolution, and paved the way for the global economy in which we live today. That mercury was central to this process was not lost on royal officials. Writing in the early 1600s, Viceroy Luis de Velasco of Peru observed that “if there was not mercury, nor would there be silver.”

Part two of this series is available here. Part three is available here.