The Spatial Distribution of Characterised Fly-Ash Particles and Trace Metals in Lake Sediments and Catchment Mosses: Ireland

Spheroidal carbonaceous particles (SCPs) from the sediments of 48 Irish lakes were enumerated and characterised according to fuel type. The concentration of metals was determined in the surface sediments and in selected mosses from the catchments of these lakes. Generally the metal concentrations in both the surface sediments and mosses were consistent with background levels found in the remote parts of Europe. Where higher metal concentrations occurred these could often be accounted for by local geochemical sources. SCP levels in the sediments of the selected lakes along the east coast were of sufficient magnitude to suggest a transboundary influence notwithstanding local sources. SCP characterisation also suggests the influence of emissions in Northern Ireland on deposition, particularly in the north-west of Ireland. There was reasonable correlation between the concentration of oil particles in the surface sediments and vanadium, but not with nickel, in mosses. SCP concentrations were not correlated with measured physical characteristics of the lakes. The level of deposition indicated is not likely to have a significant impact on human health over and above the damaging effects of urban dwelling but the adverse impact of this deposition on acid-sensitive surface waters in Ireland has been recorded.