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The scandal of the pipes illegally soldered with lead at Kai Ching Estate, which has caused great alarm in Hong Kong, was certainly over-blow. I am not a doctor but it seems that the ingested quantity of the heavy metal was too low to cause health damages: 10.8 to 35.1 micrograms, even if it still higher than the WHO level of 10 micrograms per liter. A few Hong Kong citizens have tested for dangerous high lead levels in their blood but it should be investigate where that have absorbed it, not only from drinking water, but also from medicines, paints and tainted food.
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 is 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) don’t exist in an elemental state but it is a by-product of silver mining, extracted from galena ore which is then crushed and smelted. The advantage of its low melting point and malleability of lead made it a favorite for the Romans plumbers who were producing pipes to be inserted into walls and underground by hammering them out from rolled sheets.
The poisonous nature of the metal was not 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 – widely used then to sweeten wines and fruits which otherwise would have tasted 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 in this case 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 and was always diluted 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 of 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 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 Romans diluted their wine with water and tended to drink the best quality were defrutum had not been added to correct the taste of a cheap wine. The poet Valerius Martial writes of a wine merchant from Marseille not willing to visit Rome after he had sold, afraid to have to drink it himself (Epigrams, X, 36).
Perhaps in a thousand years Hong Kong will have lost its shine towards Shanghai and then there will be a Chinese historian who will try to explain such strange fact with our lead-tainted waters. He will argue that proof of it could be found in our low birth-rate, irritability, constipation, difficulty to concentrate and grasp reality.
Angelo Paratico