Heavy metals in petroleum-contaminated surface soils in Serbia.

Investigation of heavy metal contamination levels as well as their association types with substrates in petroleum-contaminated surface soil was carried out using modified sequential extraction method. In that way, remobilization capacity of metal cations, both in natural conditions and in accidents, has been studied. Moreover, partitioning of heavy metals, originating from spilt oil derivative, among surface soil substrates was estimated. Extreme contamination with lead was discovered, as well as the increased concentrations of zinc and copper. Oil-derived Pb and Zn were found to be distributed between carbonates and amorphous Fe-oxides, whereas Cu was found to be dominantly associated with amorphous Fe-oxides. Appreciable amounts of these metals were also found to be incorporated into more resistant structures. In petroleum-contaminated surface soil, substrates of cadmium are carbonates, whereas nickel has the great affinity toward hydrous Mn-oxides. Cd is proven to be the most mobile metal in oil-contaminated surface soil.