Natural and anthropogenic influences on geochemistry of soils in terrains of barren and mineralized carbonate rocks in the Pb-Zn mining district of Mezica, Slovenia

Soil samples were collected at 147 locations in a 1 km(2) grid pattern in southern Austria and northern Slovenia in order to evaluate natural versus anthropogenic influences of Pb-Zn mining and smelting activities in this area. The territory consists predominantly of Triassic limestones and dolomites containing Pb and Zn ore bodies. Total concentrations of 26 chemical elements in 507 soil samples were determined by X-ray fluorescence spectrometry. Elemental distributions were studied by univariate statistical analysis and by R-mode factor analysis. 79% of the total variability in data is explained by four factors. The factor that is loaded with Pb and Zn explains more than 10% of the variance. Results of the statistical analysis were plotted as elemental and factor score geochemical maps. The results show that concentrations of most elements increase on the average with soil depth. Several elements (Cr, Cu, Ni, Pb and Zn) tend to accumulate in organic horizons. They indicate heavy airborne technogenic pollution from the time of operation of the smelter at Zerjav. Geochemical maps indicate distinctions in elemental concentrations in soils on different bedrock and in different soil types as well as sources of elemental enhancement in soils. Besides the significant technogenic anomaly of Pb and Zn in the top few centimetres of the soil in the vicinity of the smelter, geogenic influence of mineralized bedrock on illuvial horizons in several places is indicated. (C) 2001 Elsevier Science B.V. All rights reserved.