During the heyday ofRoman Empireroads stretched in every direction, connecting distant provinces. The mines worked tirelessly to unearth buried treasure, while the smelters turned raw silver into coins that supported the economy of an entire civilization. But behind the progress and efficiency of the time there was an invisible and devastating enemy: lead.
According to a recent study, lead levels in the air at the height of the Empire were so high that they caused a 2.5-3 point reduction in the average IQ of Europeans. This conclusion was reached through the analysis of ice cores extracted in Greenland, which preserve traces of the atmosphere of the past.
Joe McConnellclimate scientist from Desert Research Institute in Nevada and lead author of the study, described the ice as a “natural archive” that preserves successive layers of environmental history. The study highlighted peaks in lead pollution that coincide with the periods of greatest economic prosperity in the Roman Empire.
The production of coins in ancient Rome involved the use of lead-rich minerals, such as galena, which released huge quantities of toxic particles into the air during the melting process. For every ounce of silver obtained, thousands of ounces of lead were dispersed into the environment, transported by the winds even to the frozen wastes of Greenland. According to McConnell, the pollution was so widespread that no one could completely escape it.
The regions closest to the mines, such asIberia (today’s Spain), were the most affected, but the problem extended far beyond. The study estimated that during the Empire’s approximately 200 years of heyday, more than 500 kilotonnes of lead were released into the atmosphere.
A comparison with modern exposure levels reveals that lead air pollution in ancient Rome was about double what children in the United States are exposed to today. Furthermore, it represented about a third of the levels recorded in the 1970s, before leaded petrol was banned.
A silent enemy
Lead is an extremely dangerous neurotoxicant, and there are no levels of exposure considered safe. Once ingested or inhaled, it disguises itself as an essential mineral such as calcium, overcoming the body’s biological defenses and accumulating in the brain. Here it interferes with fundamental processes, such as the formation of synapses, the myelination of nerve fibers and the functioning of neurotransmitters, thus compromising cognitive abilities and mental health.
In children, the impact is even more serious: lead can cause attention deficit, emotional difficulties and delays in cognitive development. Nathan Chellmanco-author of the study, explained that a 2-3 point reduction in IQ might seem negligible on an individual level, but on a European scale it represents a problem of enormous proportions.
Air pollution wasn’t the only problem: lead was present everywhere in ancient Roman daily life. It was used in plumbing systems, kitchenware, and even as a sweetening additive wine. This widespread use has led many historians to speculate that lead played a significant role in the decline of the Empire.
Bruce Lanpheara professor of public health, said that lead probably contributed to the collapse of Rome, although it was not the only factor. The Empire, already weakened by political, economic and health crises, may have suffered further damage from the systematic poisoning of its citizens.
Lessons from the past
Lead is not a threat confined to the past. After the fall of the Roman Empire, emissions of this toxic metal increased with the industrial revolution, reaching unprecedented levels. In the 20th centuryleaded gasoline caused an explosion of contamination, with pollution levels 40 times higher than those of Roman times.
Although regulations have dramatically reduced exposure in industrialized countries, the problem persists. In developing countries, half of children are still exposed to dangerous levels of lead. According to a recent report, at least 1.5 million people die each year from cardiovascular disease related to lead poisoning, with a global cost of approximately $6 trillion.
The study on lead pollution in the Roman Empire highlights how human activity has always profoundly influenced the environment and human health. McConnell described the Roman case as the first documented example of the impact of human activities on the ecosystem.
Lead, which poisoned citizens and perhaps hastened the decline of the Roman Empire, stands as a warning to the modern world. Faced with today’s environmental challenges, history demonstrates how crucial it is to learn from our mistakes to protect the health of the planet and humanity itself.
