Mercury, toxic to humans, is the only known metallic element that is liquid at standard Earth temperature and pressure and therefore poses a hazard to children because of its coolness. However, numerous historical human activities have involved the use of mercury, including gold and silver mining, the production of the red pigment vermilion, felt production, and the manufacture of mechanical pressure gauges, thermometers, and other devices. One individual even created a mercury fountain for the Spanish Pavilion at the 1937 World Exhibition in Paris, which is now on display at the Fundació Joan Miró in Barcelona.
Throughout the centuries, a significant amount of mercury has been used industrially, leading researchers to investigate the presence of legacy mercury. This element can persist in the environment indefinitely, posing a toxic hazard to humans and other forms of life. Saul Guerrero and Larissa Schneider from the Australian National University have now developed a comprehensive historical dataset on the global trade and production of mercury before 1900, country by country. Their study has been published in the Proceedings of the National Academy of Sciences.
As primary sources, the authors examined records archived by governments, documents from local trade associations, reports of ship cargoes in newspapers, and other sources. They compiled data on the mercury market for each country, considering the net import/export balance and the fraction of domestically produced mercury that was not exported. All of this data was compiled into a “mercury source pool,” which accounts for the total historic anthropogenic mercury within and outside the global mercury biogeochemical cycle. The authors claim that this report provides unprecedented detail, establishing boundaries on the environmental impact of legacy mercury.
The use of mercury evolved from 1500 to 1900, transitioning from a monopoly held by silver refiners in the New World to a vast global market that encompassed the Western world, China, and India. The authors note that a significant amount of anthropogenic mercury before 1900 was removed from the global mercury biogeochemical cycle through chemical sequestration. This occurred either in industrial products like felt and vermilion or as an industrial byproduct in the form of calomel, a solid mercury chloride mineral buried within a mineral matrix.
In the 19th century, China alone accounted for 20% of the global mercury market, both as a consumer and exporter. This means that a substantial amount of mercury was chemically sequestered as vermilion and therefore did not contribute to the global mercury biogeochemical cycle. The authors argue that gold rushes, previously believed to be a major source of anthropogenic mercury deposits, do not account for a significant percentage. They cite the unexpectedly low use of mercury by gold miners in Australia.
2023-08-20 10:00:04
Article from phys.org
