Speciation of beryllium, nickel, and vanadium in soil samples from Csepel Island, Hungary

Sequential leaching methods have been used for the speciation of Be, Ni, and V in five soil samples from Csepel Island on the Danube river located near an oil-fired power plant. The concentrations of the elements of the extracts were determined by inductively coupled plasma mass spectrometry. The total efficiency (the sum of the extracted metals divided by metal fraction which is soluble in aqua regia) of the five-step method was always higher. The difference for Ni was considerable, because of the high abundance of Ni found in the moderately reducible fraction, which is absent from the three-step method. The sum of the mobile species (exchangeable, carbonatic, and easily reducible) determined by both methods, were in reasonable agreement; this was not so for the individual fractions. There were greater differences between the non-mobile fractions (moderately reducible and oxidizable), because of the presence or absence of the moderately reducible fraction. For both methods there was good correlation between the oxidizable fraction and the organic matter content of the soils.