Ice in glaciers building up over the millennia is a superb source of information on ancient atmospheric conditions. Most glacial ice is in the poles, but not all. As new layers of water freeze on glaciers and ice sheets, they solidify with bubbles of air and particles. These bubbles in the ice contain actual samples of ancient air.
That is one way scientists have demonstrated historic and prehistoric carbon dioxide levels, and how they have shown when massive volcanic eruptions darkened the skies worldwide, littering the ice with ash. Now, taking cores from the Col du Dome glacier on Mont Blanc in France, they have shown how the ancient Romans poisoned not only themselves, but the air in Europe with their lead mining.
The human romance with metal goes back almost 10,000 years, but the earliest method of obtaining copper from stone was to hammer it out of ore-rich rocks, without heating. Actual smelting seems to have begun about 7,000 years ago, in Serbia, where copper slag has been found from that time. Lead’s time would come early too, though how early is controversial.
Both copper and lead found in Çatal Höyük, Turkey, from about 8,500 years ago, seem to be “native” – hammered cold out of the rock. In 2015 a team of Israeli archaeologists reported in PLOS One about a bi-conical bead-like object made of almost pure lead hafted onto a wooden shaft in a cave in the Negev. Its purpose is entirely mysterious, but in any case the shaft enabled carbon dating, which turned out to be the Late Chalcolithic period (Copper Age), toward the later part of the fifth millennium B.C.E. – around 6,000 years ago. Isotopic analysis indicates that the wood was tamarisk and was local to the Negev.
But the lead came from Turkey – the Taurus range in Anatolia. So even if the earliest lead artifact was found in Israel, in Ashalim Cave, either the ore was imported, or the bead was made in Turkey. Even so, according to Naama Yahalom-Mack and the team, the ancient world had little use for lead except to weigh down fishing nets, as described by authors from Pliny to Ovid and more. But lead was mainly a byproduct of silver smelting. Until the Romans discovered the malleable metal’s charms, one being its low melting point, another being that it wasn’t rare.
They continued to use it for fishing net sinkers, examples of which were found in a Roman-period shipwreck off the Israeli coast in 2013. But the Roman use of lead went much, much farther.
Plumbing the depths
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Famously, the ancient Romans used lead to manufacture water pipes. The modern word “plumber” originated in the Latin word plumbum, meaning lead. But that was far from all. They used lead in everything from jewelry to cookware to tableware. They would boil their stews and wines in pots made of lead, or lined with lead, or made of alloys including lead.
Then they might eat their meals off lead plates, and drink their wine from a lead cup. They had other pots, plates and cups, but they liked lead ones. Romans put lead into their cosmetics and even cooked with it – and before your eyebrow falls off, just think of today’s gourmands and the mania for gold leaf on hamburgers and sushi and ice cream.
Yes, it is a thing and no, it shouldn’t be. All you will get from that is expensive bowel movements. Don’t eat charcoal ice cream either. Back in ancient Rome, lead featured in 20 percent of the 450 recipes in the Roman Apician Cookbook (De re coquinaria), which was associated with the Roman gourmand Apicius, according to a study from Dartmouth.
That study notes that lead was thought to have sweet overtones. They even created a thing called “sugar of lead”, which was boiled-down grape juice cooked in lead pots. A latter-day recreation of sugar of lead produced a syrup with a lead content of 2,900 parts per billion, which is 1,000 times the acceptable daily dose today.
To use that much lead, the Romans had to mine it heavily, and they did. Italy itself didn’t have much in the way of metal ore, but the rest of the empire did. The hunger for metal is thought one of the reasons Caesar wanted to conquer the pesky and mainly distant isle of Britain: for its tin and its lead (why else would he want it).
Pliny the Elder would write extensively about Roman ore mining before being killed by Mt. Vesuvius in Pompeii in 79 C.E. Roman-era mining activities increased atmospheric lead concentrations in Europe at least 10-fold, according to analysis of the Mont Blanc ice cores. Let’s have some proportion, though. Motor vehicles powered by leaded gasoline have increased the atmospheric concentration of lead 100-fold compared the natural state.
However, even without cars belching out emissions, the Romans managed to achieve significant metal pollution during the Roman Republican and the Imperial period: during the centuries before the common era and up to the second century C.E. There were much lower levels before and after, at least until cars were invented.
Contemporary ice cores from Greenland do not show such contamination. How many slaves and nameless locals died in the service of Roman mining, not the safest of ventures, cannot even be surmised. However, they may have had the last laugh.
Lead them to it
Never mind its rise: the fall of the Roman empire may well have had to do with their love of lead. Formally the great and mighty city ended its rule when Vandals sacked it in 455 C.E., but many a scholar thinks the Romans were fatally weakened by the sheer extent of lead poisoning they suffered, over generations no less.
Lead is toxic even in small doses. Unlike other metals such as zinc, copper and iron, it plays no role whatsoever in mammalian physiology. It does nothing but bad things, nothing. The symptoms of lead poisoning include mental retardation and stunting in the young, fatigue and mental derangement and bad temper in general, and much more.
Did the ancient Romans suspect they were killing themselves with the very sophisticated water systems they had built, the creams they were smearing on their faces, their predilection for lead-laced sweets and all the rest? They most certainly did. An architect named Marcus Vitruvius Pollio who lived in the time of the great and mighty Emperor Augustus (who ruled from 27 B.C.E. until his murder in 14 C.E.) explicitly wrote of the dangers of lead in his massive book “De architectura”.
For one thing, in Volume VIII, he noted the healthy qualities of bathing in hot springs “because boiling in the soils through which they pass, they acquire many virtues… If any member of the body, either from paralysis or other malady, become useless, aluminous waters warm it, and introducing, through the open pores, the opposing power of heat, restore it, and thus it immediately regains its former strength. Bituminous waters, taken inwardly, act as purgatives, and are excellent for the cure of inward complaints.”
But don’t go near the waters of springs in areas where metals, “gold, silver, iron, brass, lead, and other similar substances, are excavated”. And this is why? “Indeed they produce effects contrary to those of the hot springs…for when taken inwardly, passing through the intestines, they affect the nerves and joints, and produce hard swellings on them.”
In chapter 6, Pollio instructs posterity how to build leaden pipes and aqueducts – and then proceeds to warn: “Water conducted through earthen pipes is more wholesome than that through lead; indeed that conveyed in lead must be injurious.” He explains why, which we know by now, and spells out: “This may be verified by observing the workers in lead, who are of a pallid color; for in casting lead, the fumes from it fixing on the different members, and daily burning them, destroy the vigor of the blood; water should therefore on no account be conducted in leaden pipes if we are desirous that it should be wholesome.” So they knew. But like every single person who smokes, eats sugar or drinks alcohol today – so they know. So what.