engleski

BASELINES FOR POTENTIALLY TOXIC ELEMENTS IN SOILS DEVELOPED ON KARST IN CROATIA

Regional geochemical baselines in topsoil developed on karst in Croatia were determined for potentially toxic elements (PTE). The concentrations of PTE in the Croatian karst soils differ due to mineralogical composition but due to two different types of climates which influence pedogenesis (mountain and Mediterranean). Some of the PTE (Pb, Cd, Zn, Se and Hg) correlate with the amount of annual rainfall which in mountain areas is > 3500 mm. A total of 894 sampling sites were analyzed covering 50% of Croatian karst (the northwestern part) region. Evaluation of anthropogenic impact on soils developed on karst evaluated by calculation of enrichment factors and their mobility potential was assessed with various chemical extractions. Total concentrations and aqua regia extracts were used to evaluate the extraction capacity of aqua regia for PTE, since this method for determination of PTE in soils is defined by Croatian environmental protocols. Soils were found to be mostly impacted on a regional scale by Pb, Cd, Zn, Hg and Se and locally Cu by agricultural activities. The distributions of Cr, Ni, Co, Mn, Mo, V and As are linked substantially to pedogenic processes and content of clay minerals, Fe-Mn oxides and soil organic matter. Lead as the most pronounced PTE had concentrations higher then the determined upper background threshold concentration values at 73 sites, also 45 sites were found to have enrichment factors >2 for Pb at 45 sites, factor scores for the Pb, Zn, Cd, Hg association of elements had high scores at 63 sites.

soil; heavy metals; pollution; karst; Croatia

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