Burton, E.D. and Hawker, D.W. and Redding, M.R. (2003) Sludge-Derived Cu and Zn in a Humic-Gley Soil: Effect of Dissolved Metal-Organic Matter Complexes on Sorption and Partitioning. Soil & Sediment Contamination: an International Journal, 12 (1). pp. 23-46.
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Article Link(s): http://dx.doi.org/10.1080/713610959
Publisher URL: http://www.informaworld.com
A sequential extraction scheme was combined with sorption isotherm analysis in order to investigate sorption of sewage sludge-derived Cu and Zn to the A-horizon of a humic-gley soil as a whole, and to the operationally defined exchangeable (1 M MgCl2), carbonate (1 M NaOAc), Fe/Mn oxide (0.04 M NH2OH.HCl), and organic (0.02 M HNO3+ 30% H2O2) soil fractions. Sorption parameters were compared for a sample of sludge leachate (with 97.4% of Cu and 63.2% of Zn present as dissolved metal-organic matter complexes, as calculated by geochemical modeling involving MINTEQA2 and verified using an ion exchange resin method) with that of a reference solution exhibiting the same chemical characteristics as the leachate, except for the presence of dissolved organic material. Dissolved metal-organic matter complexes were found to significantly (P < 0.05) depress sorption to the bulk soil and each fraction. The greatest depression of Cu and Zn sorption was observed for the exchangeable, carbonate, and Fe/Mn oxide fractions, while the organic fraction of the soil was the least affected. This reflects a greater affinity for the exchangeable, carbonate, and Fe/Mn oxide fractions by the free divalent metal (Cu2+, Zn2+), with sorption by these fractions attributed to cation exchange, chemisorption, and co-precipitation processes. The sorption characteristics of the organic fraction indicated that Cu and Zn sorption by soil organic matter mostly involved dissolved metal-organic matter complexes. This may be attributed to hydrophobic interactions between non-polar regions of the dissolved metal-organic matter complexes and solid-phase soil organic matter.
|Additional Information:||© The Association for Environmental Health and Sciences. © Taylor & Francis.|
|Keywords:||Heavy metals; speciation; sequential extraction; sewage; soil; organic matter.|
|Subjects:||Agriculture > Agriculture (General) > Soils. Soil science|
|Deposited On:||07 May 2004|
|Last Modified:||19 Nov 2010 05:02|
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