Lead traces in Italy’s Bay of Naples provide insight into ancient Roman history

Science : Sediment cores taken from the harbor of Naples, Italy, are being used to study Roman expansion in the area over a period of some 500 years. The cores show traces of various iron isotopes, which flowed into the harbor through the elaborate lead-pipe aqueduct system the Romans constructed. From the different isotopes, researchers have been able to determine where the lead was mined and thus start mapping out a timeline of urban development in the region. One discovery, reported in the Proceedings of the National Academy of Sciences, was a sudden shift in lead content about AD 79, when nearby Mount Vesuvius erupted. That shift suggests that the aqueduct pipes may have become damaged during the eruption and were subsequently repaired with lead mined from a different location. In addition, the researchers say that over time the lead came from sources increasingly farther from Naples, which indicates that the aqueduct network continued to expand for hundreds of years.