We sometimes think of environmental pollution as a modern scourge, but recent research shows that man-made pollutants have been with us much longer. The plague known as Black Death ravaged Europe between 1347 and 1351, when it killed around 20 million people. In those five short years, the population took an enormous hit. According to information gleaned from ice cores, in which layers have formed over thousands of years, those dates coincide with a sudden drop in lead in the air.
Lead pollution is typically considered a hallmark of industrial society, but a growing body of research suggests human activity has been fouling the air with harmful heavy metals for millennia. Results of a new ice core analysis, published last week in the journal GeoHealth, support the idea that in Western Europe at least, mining and smelting activity has tainted the air with lead for at least 2,000 years. In fact, the only sliver of time during which the scientists’ instruments sniffed lead-free air was from 1349 to 1353, when folks were presumably too busy dying in droves to work the mines.
“With the closing of the mines, you can see the levels of lead dropping to zero,” Alexander More, a historian of science at Harvard University and lead author on the new study, told Gizmodo. “We can go down to the month of the arrival of the plague, and you can see the immediate drop, right along mining activity.”