Mercury Production and Use in Colonial Andean Silver Production: Emissions and Health Implications

Abstract

Background: Colonial cinnabar mining and refining began in Huancavelica, Peru, in 1564. With a local source of mercury, the amalgamation process was adopted to refine silver in Potosí, Bolivia, in the early 1570s. As a result, large quantities of mercury were released into the environment. Objectives: We used archival, primary, and secondary sources to develop the first estimate of mercury emissions from cinnabar refining in Huancavelica and to revise previous estimates of emissions from silver refining in Potosí during the colonial period (1564–1810). Discussion: Although other estimates of historical mercury emissions have recognized Potosí as a significant source, Huancavelica has been overlooked. In addition, previous estimates of mercury emissions from silver refining under-estimated emissions because of unrecorded (contra-band) production and volatilization of mercury during processing and recovery. Archival descriptions document behavioral and health issues during the colonial period that are consistent with known effects of mercury intoxication. Conclusions: According to our calculations, between 1564 and 1810, an estimated 17,000 metric tons of mercury vapor were emitted from cinnabar smelting in Huancavelica, and an estimated 39,000 metric tons were released as vapor during silver refining operations in Potosí. Huancavelica and Potosí combined contributed > 25% of the 196,000 metric tons of mercury vapor emissions in all of Latin America between 1500 and 1800. The historical record is laden with evidence of mercury intoxication consistent with effects recognized today. Our estimates serve as the foundation of investigations of present-day contamination in Huancavelica and Potosí resulting from historical emissions of mercury.

Observational and Modeling Constraints on Global Anthropogenic Enrichment of Mercury

“…More detail on the amalgamation process can be found elsewhere. 26,105 Figure 3. Observational constraints (gray bars) on model sensitivity simulations (symbols).…”

Historical (1850–2010) mercury stable isotope inventory from anthropogenic sources to the atmosphere

“…The Au/Ag mining uses liquid Hg 0 to amalgamate Au/Ag ores. Mercury is evaporated by roasting the Au/Ag-Hg amalgam at temperatures >1000 °C to obtain Au/Ag (Robins and Hagan, 2012;Velásquez-López et al, 2010). This process involves a high-temperature, near-complete physical transformation of liquid Hg 0 to GEM, and should induce insignificant Hg MDF (Laffont et al, 2011).…”

“…Natural atmospheric Hg emissions from volcanoes, crustal weathering and hydrothermal activity are thought to be 1-2 orders of magnitude smaller than modern anthropogenic Hg emissions (Amos et al, 2015;Bagnato et al, 2014;UNEP, 2013). Prior to the 1850s, anthropogenic Hg releases mainly came from primary Hg mining and use of Hg as amalgamation agent for silver extraction in the Spanish colonial Americas (Camargo, 2002;Hagan et al, 2011;Robins and Hagan, 2012). Following the industrial revolution, anthropogenic Hg releases further increased due to large-scale gold mining, non-ferrous metal production and combustion of fossil fuels (Streets et al, 2011).…”

Residential metal contamination and potential health risks of exposure in adobe brick houses in Potosí, Bolivia

“…By the early 1570s, mercury amalgamation was adopted for silver refining, resulting in the release of mercury and other toxic compounds into the surrounding air and watershed of the city (Robins, 2011). Between 1564 and 1800, it is estimated that 39,000 metric tons of mercury vapor were released from the silver refining operations in Potosí (Robins and Hagan, 2012). As the production of silver began to decline in the late 1800s, mining for other metals, primarily tin, lead, and zinc, increased, and these operations continue today, with an estimated 20,000 miners working old mine tailings or new mine shafts at Cerro Rico (Strosnider et al, 2011).…”