The analysis of almost 200 Scottish Sphagnum moss samples collected over the past 170 years has revealed trends in the isotopic composition of lead similar to those previously established for dated Scottish lake sediments and peat bogs, lending credibility to these proxy records of atmospheric lead contamination and deposition. The effect of temporal variations in contributions from sources such as smelting of indigenous lead ores (206{sup left}Pb/207{sup left}Pb～1.16-1.18), coal combustion (206{sup left}Pb/207{sup left}Pb～1.17-1.19), and the use of imported Australian lead (206{sup left}Pb/207{sup left}Pb～1.04) was clearly seen in the Scottish moss 206{sup left}Pb/207{sup left}Pb record. This showed some differences from the corresponding archival herbage record for the south of England, where the initial influence of Australian lead occurred earlier, at the end of the 19th century. A significant decline from a 206{sup left}Pb/207{sup left}Pb value of ～1.17 in the Scottish moss record began in the 1920s and continued until the 1980s (206{sup left}Pb/207{sup left}Pb～1.12). The success of measures to reduce lead emissions to the atmosphere over the past 20 years in the U.K., in particular from petrol-engined vehicles using alkyl lead additives manufactured primarily from Australian lead, is evident in both the increasing 206{sup left}Pb/207{sup left}Pb ratio and falling lead concentration data for Scottish moss.
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