Evidence of large scale heavy-metal contamination of natural surface soils in Norway from long-range atmospheric transport

Results from a nationwide survey of natural surface soils show several heavy metals to be present in substantially higher concentrations in southernmost Norway than in areas farther north. Mean values in this region are as follows (corresponding values from the far north in parentheses): Pb, 111.3 ppm (8.7); Zn, 84.1 ppm (34.6); Cu, 13.5 ppm (8.7); As, 5.9 ppm (1.1); Sb, 2.4 ppm (0.22); Se, 2.0 ppm (0.23); Cd, 1.38 ppm (0.18). The concentrations of most metals decrease regularly along a northerly gradient. Comparison with data from other investigations in Norway regarding air pollution with heavy metals and levels of metals in different soil horizons strongly suggest that long-range transport of metals from other parts of Europe is the main reason for the excess accumulation of metals in the southern topsoils. Only in the case of Cu was this source found to be of minor importance. Deposition from metal smelters within Norway and in bordering areas of Russia are shown to cause elevated levels locally of copper and zinc in particular. High relative levels of Se in coastal areas at all latitudes are assumed to be derived from airborne transport of Se originating from biogenic processes in the ocean.