9:30 AM - 9:45 AM
[BCG06-03] Chemical speciation and solubility of heavy elements (lead, zinc, copper, arsenic and cadmium) in contaminated soil from Kamegai mine tailing, Toyama, Japan
Keywords:soil, heavy metals, speciation
Thirty-two soil samples were analyzed, determining the chemical fractionation of Pb, Cd, As, Zn and Cu using by the five-step sequential extraction (SEP), X-ray absorption fine structure (XAFS), X- ray diffractometer (XRD) and scanning electron microscopy. The results of SEP showed that most of the Pb was associated with non-residual fractions, mainly in crystalline iron oxides (goethite). The Cd appeared mainly associated carbonate fraction in the roots of the dried plants in the soils. The XAFS spectra of the samples showed that Pb in the soil are adsorption forms with Fe-(hydr)oxides surface. Results of XAFS analysis showed Cd in the samples are CdCO3, coprecipitated with CaCO3. Zn, Cu and As appeared mainly associated with the amorphous and crystalline iron oxides. Heavy metals associated with carbonates, amorphous and crystalline iron oxides, thus being potentially more mobile to the environment if conditions were more acidic or reducing.
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