Speciation of vanadium in urban, industrial and volcanic soils by a modified Tessier method

Vanadium (V) concentrations in industrial, urban and volcanic soils were sequentially extracted using a modified Tessier's method. The voltammetric technique was used to determine V concentrations in solutions obtained from the various extraction steps. At the reference stations, the V concentrations (sum of four individual fractions) in soils ranged from 0.72 to 0.24 g kg-1 dry weight (d.w.) with a mean value of 0.18 g kg-1 d.w. V concentrations in soils of the Palermo urban area ranged from 0.34 to 2.1 g kg-1 d.w., in the Milazzo (industrial) area between 0.26 and 5.4 g kg-1 d.w. and in the volcanic area near Mt. Etna from 0.91 to 2.9 g kg-1 d.w. When the V concentrations around Mt. Etna were compared with those obtained at the reference stations, it was confirmed that Mt. Etna is a continuous source of V. In all the samples analyzed, the majority of V (from 94 to 100%) was detected in the fourth fraction.