Storage and distribution of trace metals and spheroidal carbonaceous particles (SCPs) from atmospheric deposition in the catchment peats of Lochnagar, Scotland.

Lochnagar is a remote mountain lake to the south-east of the Cairngorm region in Scotland. Its catchment receives anthropogenic trace metals solely from atmospheric deposition. Ten peat cores were taken from the catchment and analysis confirmed that they have been contaminated by trace metals. The peats have an high affinity for trace metals and this results in metal accumulation in the surface peat layers. The formation of trace metal sulphides may also reduce remobilisation. In this way, trace metals derived from atmospheric deposition have been scavenged and accumulated. In contaminated peat layers, 77.4% Hg, 89.6% Pb, 93.4% Cu, 72.4% Zn and 86.5% Cd of the total stored are from anthropogenic sources. The accumulated trace metals in the peats can potentially influence the lake system through erosion. Spheroidal carbonaceous particle (SCP) profiles were used to date the peat cores. By referring to the SCP profiles in the peats and comparing these with the trace metal profiles in the lake sediments, the mobility of trace metals in the catchment peats is confirmed.