Isotopic characterisation of the historical lead deposition record at Glensaugh, an organic-rich, upland catchment in rural N.E. Scotland

The mean anthropogenic Pb inventory of the four longer cores was 7.4±1.5 g m−2, of which ∼70% occurred in the top 10 cm, in good agreement with the inventories of the shorter cores collected above 400 m. These inventories are higher than those of the industrial central belt of Scotland, probably because of enhanced deposition at altitude. This is consistent with the derived average 210Pb flux of 198±11 Bq m−2 year−1, which is twice that of typical UK 210Pb deposition and the rainfall for the site. The past deposition of Pb at Glensaugh, including that from sources (e.g., smelting, coal combustion) other than leaded petrol, has clearly been considerable. Even since the introduction of leaded petrol ca. 1930, car-exhaust emissions may have accounted for no more than 35% of the Pb deposited.