[ti:Researchers: Oldest Evidence of Lead Pollution Found in Greece]
[al:Science & Technology]
[ar:VOA]
[dt:2025-02-10]
[by:www.voase.cn]
[00:00.00]Ancient Greece produced the earliest records of democracy - and, scientists now say, lead pollution.
[00:10.75]That is the finding of a study that recently appeared in Communications Earth and Environment.
[00:20.76]The researchers studied sediment cores removed from mainland Greece and below the Aegean Sea. 
[00:29.95]They found in the cores the oldest known evidence of lead pollution in the environment dating back around 5,200 years.
[00:43.04]That is 1,200 years older than the former oldest evidence of lead pollution.
[00:52.11]That evidence was discovered in Serbia.
[00:56.61]In ancient times, lead was released into the atmosphere as a product of copper and silver production.
[01:06.34]The toxic, or poisonous, metal turned to dust over time and settled onto the soil.
[01:15.66]Joseph Maran of Heidelberg University was a co-writer of the new study.
[01:22.79]"Silver was used for jewelry, for special objects - but it wasn't found in a pure state," it was mined in ore combined with lead, Maran said
[01:38.32]The place with the earliest signs of lead is in northeastern Greece, near the island of Thasos.
[01:47.35]Past evidence suggests Thasos was one of the area's most important places for silver mining and metalwork, said Maran.
[01:59.08]Yale historian Joseph Manning, who was not involved in the study, said "Lead released from smelting is the world's first form of toxic or industrial pollution."
[02:14.78]The researchers found that levels of lead contamination remained fairly low in ancient Greece.
[02:22.67]The levels remained low throughout the Bronze Age, the Classical period and the Hellenistic period. 
[02:32.12]The Classical period is famous for Athenian democracy, and the thinkers Socrates and Plato.
[02:41.91]And the Hellenistic period saw Greek cultural influence reach its height across the Mediterranean.
[02:50.45]But the new study shows that around 2,150 years ago "a very strong and abrupt increase" in lead releases caused by human activities took place across Greece, said co-writer Andreas Koutsodendris of Heidelberg University.
[03:13.94]Around that time, the Roman army won control of the Greek peninsula, completely changing the area's society and economy. 
[03:24.99]As Roman trade, colonies and shipping grew across the Mediterranean Sea and Black Sea, demand for silver coins also grew. 
[03:38.18]As a result, more smelting was required, Koutsodendris said.
[03:44.59]Later the Roman Empire used lead to make tools for eating and building, including pipes.
[03:53.11]Past research - including a study of ice cores from Greenland - had detected high levels of lead across much of the Northern Hemisphere during Roman times.
[04:07.57]But the new study adds a more exact "and local picture to how lead levels changed," said Nathan Chellman. 
[04:18.09]Chellman, an environmental scientist at the University of Nevada, Reno, was not involved in the research.
[04:28.34]I'm John Russell.