Partitioning of heavy metals in contaminated soils

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6272165

Hickey, M G

Three soils and a sediment which had undergone massive prior additions of heavy metals were sequentially extracted so that Cd, Cu, Ni, and Zn could be partitioned into five operationally defined geochemical fractions: exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter, and residual. The highest amount of Cd (ca. 37%) was found in the exchangeable fraction, and Cu was the only metal significantly associated with the organic fraction. The Fe-Mn oxide fraction contained 23, 24, 26 and 39%, and the residual fractions 15, 34, 55, and 14%, of the Cd, Cu, Ni, and Zn respectively. The following hazard order may be proposed for these highly contaminated materials: Cd > Zn > Cu > Ni. Bio-Gel P-2 was used to separate Cu-organic complexes from inorganic-Cu. Continuous elution with 0.03 ..mu..g ml/sup -1/ Cu, Cd, and Zn in 50 mM KCl prevented adsorption of metals by the gel and subsequent dissociation of labile metal-organic complexes. Overestimates of exchangeable Cd, Cu, and Zn can result from anion complexation and formation of soluble metal-organic complexes. Two soils, contaminated with heavy metals, were extracted with 1.0 M MgCl/sub 2/, Mg(NO/sub 3/)/sub 2/, and Mg(ClO/sub 4/)/sub 2/. Gel chromatography was used to quantify the amounts of inorganic and organically complexed metals. MgCl/sub 2/ and Mg(NO/sub 3/)/sub 2/ extraction overestimated the truly exchangeable Cd and Zn. 1.0 M Mg(ClO/sub 4/)/sub 2/ provided a good estimate of truly exchangeable Cd and Zn and of water soluble Cu. Extraction with this solution may be a good measure of potential environmental hazard.

• OSTI ID: 6272165
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CADMIUM
CHEMISTRY
CHROMATOGRAPHY
CONTAMINATION
COPPER
ELEMENTS
ENVIRONMENTAL IMPACTS
METALS
NICKEL
PARTITION
SEPARATION PROCESSES
SOIL CHEMISTRY
SOILS
TRANSITION ELEMENTS
ZINC