I had just finished Greg Woolf's Rome: An Empire's Story (2012) in which he compares Rome's Empire with a glacier and melting ice cap, when I received the following question from email that was relevant to the book."I have read that lead was extremely valuable to the Romans. It was easy to melt, cast and shape. Pipes, large water cisterns, possibly even plates, bowls and cups could be fashioned from it. It was easy to repair and recycle lead articles.A NatGeo article a number of years ago indicated that analysis of ice core samples from the Greenland Ice Sheet showed evidence of massive lead smelting that would correspond to the period of Roman conquest and the expansion of the Empire. I cannot cite the source, but I recall a forensics report on Roman skeletons that found substantial lead residue in long bone fragments that led to speculation of lead poisoning or at least the negative health effects we now understand are caused by it, mainly insanity. What I have learned is that lead was extremely valuable to the Romans. Could exposure to lead have been high enough to have been a problem within the ruling and upper class?"One of the most appealing sections of Woolf's book is his look at the role of ecology in the development of Rome's empire. He summarizes the material behind the National Geographic reference in the email query."New evidence for increased levels of mining and metal production has come from ice cores drilled through the Greenland ice cap. To judge from the levels of atmospheric lead and copper pollution attested there, the production of metals reached a peak in the early Roman Empire not repeated before the Industrial Revolution."