Imma Perfetto
Cosmos science journalist
A new study of sediment cores from the Aegean Sea has found that lead pollution from human activities may have begun more than a thousand years earlier than previously thought.
Lead is known to have a wide range of human health impacts, especially in children for whom low-level exposure is linked to cognitive decline.
Researchers analysed lead content in marine sediment cores taken from the Aegean Sea, in the eastern Mediterranean, and a sediment core from the Tenaghi Philippon peatland in northeastern Greece.
They also analysed the pollen and spore content in the cores to investigate how the region’s ecosystems were affected by social and cultural changes in European antiquity.
In the core from northeastern Greece, they found the earliest recorded signal of probable human-caused lead pollution dating to about 5,200 years ago. This is about 1,200 years earlier the previous record, which was recorded in peatland cores from the Balkan Peninsula.
The findings indicate that the ecosystem impacts of agropastoral societies remained confined to local areas during the Bronze and Iron Ages (5200–2750 years ago).
But this changed about 2,150 years ago, when lead became ubiquitous in both terrestrial and marine environments and coincided with deforestation and agricultural expansion.
The researchers suggest this was likely brought about by a fundamental political change that occurred in the region: the expansion of the Roman Empire into Ancient Greece.
“The incorporation of Greek regions into the Roman political sphere provided the new rulers with the opportunity to benefit from the natural resources of the recently acquired provinces,” they write in the paper.
“Which led to an unprecedented increase in the exploitation of Greek mining districts in order to extract gold, silver, and other metal resources.”
Research Cosmos covered last month found that lead pollution, released by the large-scale mining and smelting of metal ores, which underpinned the Roman economy, likely caused widespread IQ declines across the Empire.
The authors of the latest study write that their new findings: “…allow us to identify the transition from local-scale environmental impact connected to agropastoralism-based economies, to more pervasive human effects on natural ecosystems linked to advanced monetised societies.
“Our data also demonstrate that the extensive use of natural resources persisted for one millennium throughout the Roman and Byzantine Empires.”
