A study has traced lead concentrations in human bones between 400 and 12,000 years in age, finding that the amount of lead they contain is connected to the amount that was being produced at the time the individuals were alive. The researchers say that this has implications for modern lead pollution.
Lead production in Europe was boosted around 2,500 years ago, as lead became used to make coins. It peaked during the height of the Roman Empire, before falling in the Middle Ages, and then starting to rise again around 1,000 years ago. Environmental records, like glaciers and lake sediments, have been shown to reflect this change in lead concentration levels, but until now the changes haven’t been seen in human remains.
The researchers took bone samples from 132 individuals – five from Sardinia and 127 from Rome – who’d been buried between 12,000 and 400 years ago. The samples were dissolved and tested for their concentration of lead, as well as a range of other metals.
The researchers found that lead concentrations in bones correlated to peaks and troughs in lead production.
“This documentation of lead pollution throughout human history indicates that, remarkably, much of the estimated dynamics in lead production is replicated in human exposure. Thus, lead pollution in humans has closely followed their rates of lead production,” says Yigal Erel, a professor at Hebrew University of Jerusalem and lead author on the paper.
“Simply put: the more lead we produce, the more people are likely to be absorbing it into their bodies. This has a highly toxic effect.”
Erel says that this should be taken into consideration as lead continues to be used in modern technologies, like batteries and solar panels.
“Any expanded use of metals should go hand in hand with industrial hygiene, ideally safe metal recycling, and increased environmental and toxicological consideration in the selection of metals for industrial use.”