Stable Lead Isotope Record of Lead Pollution in Loch Lomond Sediments since 1630 A.D.

Abstract

Stable lead isotope data can yield information on the geochemical origins of lead and on its relative contributions from sources such as coal burning, mining, smelting, and car-exhaust emissions. This extremely detailed 206Pb/207Pb profile for dated bottom sediments in Loch Lomond, Scotland, shows the trends clearly related to the varying nature and extent of anthropogenic lead inputs after 1630. In particular, a significant decline in the 206Pb/207Pb ratio of excess lead during 1929−1991 is attributable to the introduction and use of (206Pb-depleted) leaded petrol since the 1920s. This accounts, however, for just 24−53% of the excess lead deposited since 1929 and ≤19% of the total excess lead inventory. Deposition of lead from industrial (and domestic) activities has predominated overall and, on an annual basis, until at least the mid-1950s.