WASHINGTON — Ancient Greece has long been recognized for its contributions to democracy, western philosophy, and now, it appears, lead pollution as well.
Researchers who examined sediment cores from both mainland Greece and the Aegean Sea have discovered the oldest known signs of lead pollution in the environment, originating approximately 5,200 years ago. This finding is significant as it predates the previous earliest record of lead pollution, identified in a peat bog in Serbia, by an impressive 1,200 years.
The release of lead into the atmosphere during ancient times was primarily linked to the smelting processes used for extracting copper and silver from ores. Over time, this toxic metal would condense into dust, eventually settling on the land.
Joseph Maran, an archaeologist at Heidelberg University and co-author of a study recently released in the journal Communications Earth and Environment, explained, “Silver was used for jewelry and unique artifacts, but it was rarely found in its pure form; rather, it was extracted from ores that included lead.” The archaeological site containing the earliest evidence of lead contamination is in northeastern Greece, close to the island of Thasos, which is recognized historically as a major center for silver mining and metal craftsmanship.
Maran emphasized the context of these findings within historical pollution, stating, “Lead released from smelting is recognized as the first form of toxic or industrial pollution across the globe.” Despite being considered the foundation of European civilization, the researchers noted that during the Bronze Age, Classical era, and Hellenistic period, the levels of lead pollution in ancient Greece remained relatively low and localized.
The Classical period is often associated with the rise of Athenian democracy, along with prominent figures like Socrates and Plato. Meanwhile, the Hellenistic period marked the zenith of Greek cultural influence throughout the Mediterranean.
However, around 2,150 years ago, the data indicates a substantial and sudden rise in lead emissions due to human activities throughout Greece. Co-author Andreas Koutsodendris, also from Heidelberg University, attributed this increase to significant socio-economic changes following the Roman conquest of the Greek peninsula in 146 B.C. The subsequent expansion of Roman trade and colonization across the Mediterranean and Black Sea heightened the demand for silver coins, which in turn necessitated smelting processes that released lead into the environment.
Furthermore, following these developments, the Roman Empire began utilizing lead in various applications, including tableware and construction materials like pipes.
Previous studies, including an examination of ice cores from Greenland, had already identified high concentrations of lead in numerous regions across the Northern Hemisphere during Roman times. However, this latest research provides a more focused and localized understanding of how lead levels evolved during this period, according to Nathan Chellman, an environmental scientist at the University of Nevada, Reno, who did not participate in the study.
