Fate of chromium in soil

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:398189

Prokisch, J; Gyori, Z; Kovacs, B; Loch, J ^[1]

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1. Debrecen Agricultural Univ. Central Lab. (Hungary)

The chromium cycle in soil was studied with speciation of chromium. The aim was to look for the possibilities the mobilization of chromium(III) and to measure the rate of chromate reduction in nature and pot and field experiments in Hungarian soils. The authors developed a sensitive and simple method for chromium speciation with a microcolumn connected an inductively coupled plasma atomic emission spectrometer. Detection limits are convenient to measure chromium forms in a 0.01 M CaCl{sub 2} extract of a contaminated soil, but it is not enough to measure that of the uncontaminated soils. CR(VI) as chromate anion is not adsorbed on pH dependent temporary charges of clays but in strongly acidic soil. Therefore CR(VI) can be leached out easily from the top layer of soil and can be transported into the ground water. Chromate ion can be reduced to CR(III) by organic matter of soil in acidic medium. CR(VI) is more stable at higher pH and lower humus content. Thus the reduction much quicker in the upper, weakly acidic top layer. CR(VI) oxidizes the organic matter of soil. The rate of this reaction depends on pH values, the humus content of the soil and temperature. CR(III) leaching in different uncontaminated soils was studied too. There are 3 pathways of mobilization of Cr(III). When pH decreases in soil the CR(III) becomes more soluble, similarly to the aluminium(III) ion. When the soil contains large quantity of water soluble organic ligands, Cr makes complexes with them and complexes formed can be leached out from the top layer. The third possibility is the oxidation of CR(III) to Cr(VI). It could happen on surface of manganese dioxide in the well-aired top layer.

• OSTI ID: 398189
• Report Number(s): CONF-9511137--; ISBN 1-880611-03-1
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CHROMIUM
ENVIRONMENTAL EXPOSURE PATHWAY
ENVIRONMENTAL TRANSPORT
HUNGARY
LAND POLLUTION
PH VALUE
SOIL CHEMISTRY