Sometime around 3600BC, people in the Balkan peninsula reached a major milestone: their mining and metal smelting created enough pollution for us to detect it today. Our research has revealed this was the beginning of the Bronze Age in the region, and the birth of large-scale metallurgy in Europe. To give some context for how early this was: at the same time, the first ever writing was just being developed in Sumer, Mesopotamia, while Britain was still in the Stone Age. Egypt’s first pyramids were still a thousand years in the future. Peat bogs are ideal repositories for these particles because atmospheric transport is the main pathway by which pollutants can reach these sites. As peat bogs grow in small layered increments each year, they can give us a clear history of the environment in which they grew. When many such chemical analyses of known ages from the many layers of the bog are put together, a sequence of changing pollution can be developed. In our new paper published in PNAS, we present the first such record of changing pollution from south-eastern Europe, reconstructed from the changing concentrations of lead in a peat deposit from western Serbia. Read more.