Impact of lead on the fall of Rome
The toxic nature of lead is well known as well as its prior use of this metal was as piping to transport water to people’s houses throughout cities. When the Romans successfully invaded Britain in 43AD they discovered the vast deposits of lead and thus founded a huge industry which would last until the middle ages. Much of our knowledge of lead originates from the Romans, including its chemical symbol Pb which originates from the Latin word Plumbum from which we get the word plumber.
Within a similar time period, the Greeks were known to use lead as an additive to wine to make it sweeter. Although this made the wine popular, it was known to cause miscarriages and outbreaks of stomach cramps and insanity. However, this clearly did not deter anyone from its continued use.
Roman writer Columella was known to keep his wine in a lead cauldron which naturally caused there to be some lead impurities to dissolve into the wine. A single teaspoon of Columellan wine has such a high concentration of lead that it is able to cause brain damage, gastrointestinal issues, anaemia, neurological symptoms such as insanity, depressed sperm count and huge impacts on the unborn foetuses of pregnant women such as early delivery, low birth weight and impaired mental development. Effectively, one teaspoon of this wine would be enough for a person to experience all of the well-known symptoms of lead poisoning. In this way, it is possible to relate the insane nature of some of the emperors and other leaders of this empire.
When used in pipes some of it would dissolve into the water and thus be ingested by those who drank the water. In fact, the water from the pipes contained around 100 times more lead than the water from the local springs. The Romans even understood that the use of lead piping was somewhat harmful and that clay piping was safer for general use. Similarly, the Romans used it for white paint which led to the poisoning of many citizens.
Some skeletons in London have been found which show symptoms of lead poisoning. These skeletons contain more lead than those from before the Iron age, which not only highlights how lead in bones is not greatly affected by the lead in the burial environment but also the huge quantities of lead that the Romans consumed whether it was deliberate or not. However, it is unclear if this is representative of the whole population. If this were representative, it would impact the ability for the citizens to populate their cities due to the metal’s impact on the reproductive system as well as hypertension and kidney issues — this could have easily caused a decline in the population of areas such as London.
Now to the chemistry of it all, when the lead ions are taken in a small fraction and into the bloodstream, then it is taken in by the enzymes which produce haemoglobin and thus disables them, forming aminolevulinic acid. Aminolevulinic acid is what causes all of the symptoms of lead poisoning: it paralyses the gut which is what causes stomach cramps and constipation as well as fluid build up in the brain which causes headaches and insomnia. This also impacts the reproductive system and causes long term anaemia.
Lead poisoning is still an issue in today’s world but rather than it being caused by the pipes it is caused by traffic fumes and old paintings which utilised lead paint however through the introduction of unleaded petrol the issues surrounding this have been greatly reduced.
Although it is unclear the extent to which lead was involved in the fall of Rome, it is clear that many Roman citizens were impacted by lead poisoning which may have caused the populations to decline. It is also clear that the Romans understood that lead was somewhat detrimental to the health of the general public but clearly not enough to completely eliminate the use of it in general.
Sources
“Molecules at an exhibition” by John Emsley, Oxford University Press 1999, pages 216-218
