Public Release: 

Lead pollution in Greenland ice tracks historical events

Proceedings of the National Academy of Sciences

Researchers report links between records of lead pollution in Greenland ice cores and economic fluctuation in ancient societies. Lead and silver ore mining powered ancient economies, but previously reported measurements of lead pollution in Arctic ice were based on sparse sampling and inconclusive dating. Joseph R. McConnell and colleagues used precisely dated measurements of lead pollution in Greenland ice from 1100 BCE to 800 CE to uncover links between estimated lead emissions and historical events that affected the economy, including imperial expansion, wars, and major plagues. The authors measured lead concentrations in 423 m of ice core from the North Greenland Ice Core Project, and combined the measurements with an annual-layer-counting approach to develop a chronology of Greenland ice. The authors found that lead pollution increased during periods of prosperity, such as the Phoenician expansion, and peaked under the Roman Empire. In contrast, lead pollution was low during periods of instability, such as the aftermath of the Antonine plague. Furthermore, the authors report that the bullion in Rome's coinage, the denarius, reflected fluctuations in estimated lead emissions. According to the authors, the record of European lead pollution in Greenland ice provides insights into economic activities, including lead and silver mining, in ancient societies.


Article #17-21818: "Lead pollution recorded in Greenland ice indicates European emissions tracked plagues, wars, and imperial expansion during antiquity," by Joseph R. McConnell et al.

MEDIA CONTACT: Joseph R. McConnell, Desert Research Institute, Reno, NV; tel: 775-673-7348, 775-772-2418; e-mail: <>

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