Three decades of atmospheric metal deposition in Norway as evident from analysis of moss samples

Monitoring of atmospheric deposition of metals in Norway on a nationwide scale using samples of terrestrial moss started in 1977 and has been repeated every 5 years. This has facilitated a detailed record of temporal and spatial trends of metal deposition all over the country as a supplement to measurements based on bulk deposition sampling on a small number of sites. Pb, Zn, Cd, As, Sb, V, Sn, Mo, and Bi all show highest deposition in the far south due to trans-boundary pollution from other parts of Europe, but the contribution from long-range atmospheric transport to metal deposition has decreased substantially over the years. The distributions of Fe, Ni, Cu, Cr, and Co are more affected by local sources, but a decreasing time trend is also evident for these elements. Se is mainly derived from processes in the marine environment. Deposition of metals from Cu–Ni smelters in Russia situated close to the Norwegian border has shown a steadily increasing trend over the time period concerned.

► Atmospheric deposition of key metals has been monitored at 464 sites in Norway every 5 years since 1977 using moss samples.
► Deposition of Pb, Zn, Cd, As, Sb, V, Sn, Mo, and Bi from long-range atmospheric transport is decreasing.
► Pb deposition has decreased by a factor of 20 since 1977 in the south of the country.
► Cu and Ni pollution in the far north due to emissions from Russian smelters has increased regularly over the time period.
► Deposition of Se is mainly due to supply from marine processes.