Effects of SO2 and heavy metal emissions from the Kola Peninsula, NW Russia, on soil acidity parameters in NW Russia and Finnish Lapland

The effects of SO2 and heavy metal emissions derived from Cu-Ni smelters in the Kola Peninsula, NW Russia, on soil acidity parameters in the western p arts of the Kola Peninsula and Finnish Lapland are presented. Organic layer samples were collected at 39 sampling plots along lines running to the wes t from two emission point sources (Monchegorsk, Nikel) in the Kola Peninsul a. The tree cover on the sample plots consisted of Pinus sylvestris L. grow ing on dry sites. The soil type was podsolic and soil texture sorted sand. The effects of emissions from the Monchegorsk smelters on the properties of the organic layer along the sampling line can be divided into two zones: u p to a distance of approx. 100 km from the smelters there were distinct gra dients in the total Cu and Ni and exchangeable Al concentrations and to som e extent in base saturation (BS), but not in extractable S concentrations, while at greater distances to the west the emissions appear to have had no detectable effects. Despite the very low BS values close to the Monchegorsk smelter, there were no differences in pH or in exchangeable H+ concentrati ons with increasing distance from the smelter. Total Cu and Ni concentratio ns were elevated close to the Nikel smelter but were considerably lower tha n those at corresponding distances from Monchegorsk. Extractable S concentr ations along the Nikel line were not affected by emissions. BS showed a dec rease with decreasing distance to Nikel, but there were no clear relationsh ips for pH or exchangeable Al. In contrast, exchangeable H+ increased with decreasing distance to the point source. A reduction in BS in heavy-metal p olluted soils should not be taken as an absolute indication of soil acidifi cation caused by acidic deposition, because metals can also effectively dis place base cations from cation exchange sites.