PREINDUSTRIAL ATMOSPHERIC LEAD CONTAMINATION DETECTED IN SWEDISH LAKE-SEDIMENTS

DESPITE evidence from Greenland ice cores for pre-industrial atmospher ic trace-metal contamination(1,2) it is commonly assumed that air poll ution in remote areas is a recent problem caused by industrial activit ies, fossil-fuel burning and emissions from motor vehicles. Here we re port analyses of lake sediments from Sweden showing that atmospheric l ead deposition increased above background levels more than 2,600 years ago. There was a small, but marked lead deposition peak about 2,000 y ears ago, and a more significant increase that began 1,000 years ago a nd accelerated during the nineteenth and particularly the twentieth ce nturies, with a deposition maximum at about AD 1970. Before the ninete enth century industrialization, lead concentrations in lake sediments from southern Sweden had already reached 10-30 times previous backgrou nd levels as a result of atmospheric deposition. We suggest that this pre-industrial airborne pollution was derived from extensive productio n and use of lead in Europe, starting with the Greek and Roman culture s(3,4). The cumulative deposition from anthropogenic sources in pre-in dustrial times (similar to 600 BC to AD 1800) was at least as large as the cumulative deposition during the industrial period (AD 1800 to th e present).