Pre-industrial atmospheric lead contamination detected in Swedish lake sediments

Abstract

DESPITE evidence from Greenland ice cores for pre-industrial atmospheric trace-metal contamination1,2 it is commonly assumed that air pollution in remote areas is a recent problem caused by industrial activities, fossil-fuel burning and emissions from motor vehicles. Here we report analyses of lake sediments from Sweden showing that atmospheric lead deposition increased above back-ground levels more than 2,600 years ago. There was a small, but marked lead deposition peak about 2,000 years ago, and a more significant increase that began 1,000 years ago and accelerated during the nineteenth and particularly the twentieth centuries, with a deposition maximum at about ad 1970. Before the nineteenth century industrialization, lead concentrations in lake sediments from southern Sweden had already reached 10–30 times previous background levels as a result of atmospheric deposition. We suggest that this pre-industrial airborne pollution was derived from extensive production and use of lead in Europe, starting with the Greek and Roman cultures3,4. The cumulative deposition from anthropogenic sources in pre-industrial times (∼600 bc to ad 1800) was at least as large as the cumulative deposition during the industrial period (ad 1800 to the present).