In many ways, during the Roman Empire European civilization reached one of its cultural and technological peaks. And as in many advanced civilizations, the Roman one was also burdened by a problem: pollution, mainly related to lead, a toxic substance released into the atmosphere in large quantities by metal extraction and processing activities. A new study published in Proceedings of the National Academy of Sciences precisely estimated the extent of air pollution on the European continent, arriving at a stunning conclusion: between 100 BC and the second century AD, lead levels in the air were so high that they may have reduced IQ by a few points of the entire European population.
Poisoned by lead
The research is based on the analysis of some ice cores taken from the Arctic, which provided direct evidence of the atmosphere that existed in the area almost 2 thousand years ago. From this data, the study authors calculated the lead levels present in the blood of Europeans at the height of the Roman Empire, showing that they were approximately three times higher than those observed in a modern-day Western child.
Neurological damage
We are talking about approximately 3.5 micrograms per deciliter, an exposure that science has shown is sufficient to cause neurological damage. And an average decline in IQ of about 2 or 3 points. “It may not seem like much – explains hydrologist Nathan Chellman, a researcher at the American Desert Research Institute who participated in the study – but if you apply it to practically the entire European population, it starts to become a very serious problem”.
This, in short, is the situation in rural areas, where air pollution was the main source of exposure to lead. In the cities, and especially among the Roman elite, lead poisoning was probably even worse, given that the metal was used in the pipes that brought drinking water to the cities, utensils and pots were made with which food was cooked and water was stored and wine, and as a sweetener for the wine itself. Such a widespread use that some historians in the past went so far as to hypothesize that it may have been precisely the harmful effects of this substance that caused the “follies” of some famous emperors, such as those attributed to Nero, and ultimately caused the fall of Western Roman Empire.
If such radical theories have not yet been confirmed, the new study nevertheless demonstrates that the impact of the Roman metallurgical industry on the European air was truly unprecedented, at least before the advent of the industrial era and the spread of leaded petrol, during the twentieth century.