The story below is an old one I know, but it cought my eye since it states
that lead production was 80,000 tons per year around the birth of christ.
The articles seems to assume that it would take the cupilation of 80,000
tons of lead to create the 800 tons of lead deposition that has been noticed
in Greenland.

Would anyone care to guess the number of people involved in extracting that
amount of lead per year using techniques available to the Roman and other
peoples of the globe at that time? How does this compare to later lead
production levels?

Thanks

George Chaplin



ICE PACK REVEALS ROMANS' AIR POLLUTION
> Global atmospheric pollution dates back to Roman and Greek times -
long before the Industrial Revolution - according to scientists who
have detected lead fallout in samples of ancient Greenland ice.
>
> The researchers have detected small but significant quantities of
lead particles in ice cores drilled to a depth of more than a
kilometre - covering a timespan of nearly 8,000 years.
>
> They detected surges in the amount of lead - a by- product of the
process of extracting silver from lead ore - at depths corresponding
to the rise of Athens and Rome. They also found lead pollution from
medieval and Renaissance silver mines.
>
> Finding lead in ice cores represents the oldest report of
international atmospheric pollution, scientists say in today's issue
of the journal Science. "Analysis of the Greenland ice core covering
the period from 3,000 to 500 years ago - the Greek, Roman, Medieval
and Renaissance times - shows that lead is present at concentrations
four times as great as natural values from about 2,500 to 1,700 years
ago (500BC to AD300)."
>
> The researchers, led by Claude Boutron, a geologist at the Domaine
University at Grenoble in France, estimate that about 400 tons of
lead feel on the Greenland ice cap during the 800 years of the Roman
Empire.This is about 15 percent of the lead that has fallen on the
area in the past 60 years of using lead additives in petrol, they
say.
>
> Professor Clair Patterson, a geochemist at the California Institute
of Technology, in Pasadena, said the pollution came from the ancient
tradition of smelting lead ore in open furnaces in order to extract
the valuable silver. Although the process - known as cupellation -
was invented about 5,000 years ago, it was the Greeks who first
exploited it on a large scale, notably at the silver mines of Laurium
on the Aegean Sea, which financed the Greek naval victory over the
Persians.
>
> Lead smelting during Roman times was done on an even larger scale
for a much longer period. At its peak, the Romans produced airborne
lead emissions equivalent to the pollution produced at the beginning
of the Industrial Revolution 1,700 years later, Professor Patterson
said.
>
> "What we see from the ice record of the Greenland cores is that we
have been poisoning the Earth's atmosphere with lead for 2,000
years." At around the birth of Christ, silver mines were producing
about 80,000 tons of lead slag a year and at least 1 per cent of this
went into the air, he said.
>
> The scientists analysed 22 ice cores drilled to depths from between
about 300 metres to 1.3 kilometres. The deepest core corresponded to
a period 7,760 years ago, long before lead ore was smelted for
silver, which acted as a measure of background levels of lead.
>
> Professor Patterson said that the eventual depletion of the lead
and silver mines - resulting in a shortage of silver coins - led to
the decline and fall of the Roman Empire. Lead poisoning, which
results in mental deterioration, played only a minor role, he said.
>
> Steve Connor, Science Correspondent The Independent, 23 September
1994 http://www.science.uwaterloo.ca/earth/waton/icepack.html

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