Critical loads of SO4 for surface waters in the Kola region of Russia

Precipitation falling on the Kola North of Russia is severely polluted by strong acids and heavy metals emitted from large local smelters operated by the Severonickel and Pechenganickel companies. Large areas in the affected region are considered sensitive to acid precipitation due to geological and climatological conditions. Extensive surface water acidification has taken place, particularly, in the mountain and remote tundra regions. Critical loads and their cxceedances have been calculated for 370 lakes sampled in the Kola peninsula. These data indicate that the surface waters in the Kola North are highly sensitive to acidic deposition. Using the minimum values determined for each NILU grid cell, critical loads of less than 20 meq/m²yr occur in about 50 percent of the area.