Lead Poisoning in Ancient Rome and Flint, Michigan
The Democratic Party circus made a stop in Flint, Michigan, yesterday. The two contenders first promised lead-free waters to all the citizens, then they started wrestling on the usual political problems.
In Flint there is an heavy lead contamination, which was discovered in April 2014. It was made worse when Flint’s City Council changed sourcing drinking water from Detroit water and Lake Huron, switching to the corrosive Flint River waters, which caused the lead contained in old pipes to leak into drinking waters. But the problem of lead contamination is as old as mankind.
Only if ingested in great quantity lead can cause ‘saturnism’ a term coming down from antiquity when planets were thought to cause diseases to mankind. It may cause multi-organ failure and damage to the nervous system. It is particularly harmful to children below six years of age, to pregnant women and breast-feeding mothers.
There is an old theory about the Roman Empire downfall’s having been caused by lead poisoning. It was first put forward in a scientific manner in 1983 by the geochemist Jerome Nriagu in a book entitled Lead and Lead poisoning in Antiquity. It was rightly met with skepticism and then refuted but the idea was so attractive that it keeps surfacing from time to time.
It is true that pipes distributing drinking water in ancient Rome were mostly made of pure lead but the quantity ingested by Roman citizens was far too low to cause saturnism. We should also consider the fact that carbonate deposits created a natural lining inside the pipes thus leading to clogging after a few years.
Lead (Pb) do not exist in an elemental state but it is normally a by-product of silver mining, extracted from galena ore which is then crushed and smelted. The advantage of lead over other metals lays in the low melting point and malleability which made it a favorite for plumbers who were producing pipes to be inserted into walls and underground. They produced them by hammering them out from rolled sheets.
The poisonous nature of the metal was not completely unknown to the Romans. Vitruvius, the great architect writing at the time of Augustus, knew it well and was advising the use of earthen pipes.
Jerome Nriagu was aware that his theory could not stand only mentioning water pipes and he rightly thought that a far bigger amount of lead was ingested through wine and cosmetics used by women.
In fact saturnism could have been caused by the use of cooking pots made of lead, where the combination of water or wine with temperature greatly increased the problem.
Lead pots were used to cook sapa and defrutum – juice of grapes, unfermented, boiled to concentrate the fructose – which was widely used to sweeten wines and fruits which otherwise would have taste bitter and sour. This was the main kind of sweetener used by the Romans, widely used in their kitchens, as we know from various authors like Apicius, Varrus, Plinius and Cato. Bronze was not used to prepare it because it could cause the formation of verdigris which would spoil the taste of the syrup. The smaller the cooking vessel the greatest the relative quantity of lead dissolved. Thus the lead was concentrated up to dangerous levels, and even if no one was going to drink the syrup in a concentrate form but always diluted mixed in wine and to preserve fruits. Roman author Columnella was advising to add one part of the defrutum into an amphora of pure wine, therefore the concentration would have been reduced to 60 milligrams per liter.
The assumption made by Jerome Nriagu was that the Roman aristocrats were drinking 2 liters of wine each day, that is three bottles a day with a total lead intake of about 180 micrograms per liter daily but, unfortunately, there are no basis to prove that. Three bottles of wine daily would have made them dyeing of cirrhosis before succumbing to saturnism!
However it should be mentioned that they normally diluted their wine with water and the Roman ruling class and rich merchants drunk only the best quality, were defrutum had not been added to correct the taste, the cheap wines corrected with defrutum were reserved to the poor and the middle classes. The poet Valerius Martial writes of a wine merchant from Marseille not willing to visit Rome after he had sold large quantity of his wine, afraid he’ll have to drink it himself (Epigrams, X, 36).
Old pipes should be checked and, if made with lead, should be replaced, the same should be done even when lead had been used solely for welding them together.