Study of selected heavy metals binding forms in carbonate-type soil
1998
Kozakova, E. | Kandrac, J. (Univerzita Komenskeho, Bratislava (Slovak Republic). Prirodovedecka Fakulta)
Binding forms (speciation) of Cu, Pb, Cd and Ni were studied in carbonate-type soil. These metals occur in soils in various forms influencing their mobility and plant availability. A sequential fractionation procedure was carried out to isolate various organic substances from the soil. Stripping voltammetry in various modes was used to determine low and trace contents of the metals in the solid soil fractionation residues. The Cu content bound to the humic substances was 47 %. The occluded Cu forms represented 41 %, the residual form of Cu was 12 %. In comparison with Cu, Pb and Ni have a minor ability to form complexes with humic substances. This fact was confirmed by the determination of their distribution between the soil sample fractions; 35 % of Pb and 21 % of Ni were bound to the humic substances. The occluded form of Pb was 49 %, the same form of Ni represented 45 %. 18 % of the total Ni occurs in carbonates and/or basic salts. Cu, Pb and Cd do not occur in that form. The major part of Cd (65 %) was bound to the humic substances.
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