Mercury, Mining, and Empire

Without mercury, would there have been a Cerro Rico supplying silver to Europe and beyond? After depleting Potosí’s relatively rich silver ores in the mid-sixteenth century, Spaniards adjusted the long-known amalgamation process, which relied on elemental mercury, salt, water, and other reagents, to refine Potosí’s lower-grade silver ores. This new assault on Potosí’s silver gave rise to one of the more vivid images of colonial Latin American history: workers, coerced through the mita system, trudging through the amalgam of crushed silver ore, mercury, and water at a 12,000-foot elevation.Robins combines archival work and reading of published primary materials, air pollution modeling, and knowledge of medical research on health effects of mercury exposure in a superb treatment of Andean colonial mining. He argues that genocidal policies encouraged the adoption of amalgamation in Potosí, which necessitated a supply of mercury, found in Huancavelica, creating “one of the largest and longest-lasting ecological disasters every known” (p. 177). Air pollution models, driven by grounded estimates for mercury use and emissions, estimate human exposure to mercury in Huancavelica and Potosí. The models indicate, for example, that in mid-seventeenth-century Potosí, when the city had a population of approximately 160,000, mercury concentrations exceeded the US EPA’s reference value (the value below which a minimal risk is estimated) by factors of 100 to 300 near the stream that concentrated mills, and by factors of 30 to 100 in areas approximately 400 meters away from the stream.Applying his knowledge of medical studies on mercury exposure, Robins links mercury’s known health effects with descriptions made by colonial contemporaries, which he situates in a way that helps us think about the persistence of negative images of Indians: “When one takes a person who is seen as inherently inferior and vice-ridden, and poisons him with mercury such that he walks around in a daze, his teeth fall out, he drools uncontrollably and has putrid breath, it will only reinforce the initial perception” (p. 186).The use of air pollution models in Andean mining is a major contribution to environmental history and to colonial history. Colonial contemporaries knew of harmful human effects of mercury exposure. Recent scholarly treatments of colonial mining similarly acknowledge negative human effects of mercury exposure. But until Robins’s book, we had no way of thinking about whether Huancavelica or Potosí was worse for human health. How bad was potential exposure to mercury? The air pollution models help put mercury pollution in terms that we can better understand; moreover, Robins also argues that there is an “ongoing toxic legacy” of mercury and mining. For example, mud huts in Huancavelica still exude mercury vapors, harming human residents through no fault of their own.However, Robins overstates the role of silver in the rise of global capitalism, an argument he needs to maintain his larger claim: that genocidal mining was at the core of the impetus of global capitalism. Moreover, the book is more about mercury than “ecology” in a broader sense, as the title implies. Robins’s interest in solid fuel used for processing mercury and amalgam is far less sustained than his interest in mercury and silver mining and refining. Also, the eloquent passage on complex long-distance food chains sustaining Potosí (p. 40) is at odds with claims that significant mercury exposure came from the localized food chain as mercury settled on crops and soils and concentrated into animal flesh and milk (p. 109). Future scholars of food supply chains may determine whether mercury fallout may have polluted the food chains or whether food came from outside the area that might have been most polluted by mercury. Finally, maps of estimated mercury concentrations should have indicated the location of the main plaza and native districts so that claims for how elites were relatively distant from the worst concentrations (p. 130) could be supported more rigorously.The use of modeling techniques, based upon strong knowledge of the social and technical processes at work, contributes significantly to increasing our understanding of Andean silver mining. Moreover, the narrative strategy is highly engaging, following silver in the rise of global capitalism, in the labor systems that sustained mercury and silver production, into the mining and processing of mercury and silver, and back to the wider world of native communities that sustained workers. Thanks to this work, we know better the horrific human toll in two cities that were functionally connected in the production of silver

Archaeology · Colonialism · Elemental mercury · Environmental health · Geography · Mercury (programming language) · Population · Waste management · Engineering · Environmental Science · Latin American history and culture

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