HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hesterberg, D. Articles by del Castilho, P. Search for Related Content PubMed Articles by Hesterberg, D. Articles by del Castilho, P. Agricola Articles by Hesterberg, D. Articles by del Castilho, P.

Thermodynamic Modeling of Zinc, Cadmium, and Copper Solubilities in a Manured, Acidic Loamy-Sand Topsoil

Dep. of Soil Sci., Box 7619, North Carolina State Univ., Raleigh, NC 27695-7619;

Jan Bril and P. del Castilho

DLO-Institute for Soil Fertility Research, P.O. Box 300003, 9750 RA Haren, The Netherlands.

^* Corresponding author.

ABSTRACT

Soil solution samples collected during a 14-mo period from manured, loamy-sand soil profiles in the Netherlands showed variations in dissolved Zn, Cd, and Cu concentrations of up to two orders of magnitude. To try to account for variations in the dissolved metals, a thermodynamic model was developed for the chemical-equilibrium computer program CHARON. In addition to solution complexation and solid-phase precipitation of inorganic components, the model accounted for metal complexation with dissolved organic carbon (DOC) ligands and with a solid organic matter (OM) exchanger phase. Both dissolved and solid organic materials were assumed to behave like fulvic acid having a complexing capacity for Zn²⁺, Cd²⁺, Cu²⁺, Ca²⁺, Mg²⁺, and Al³⁺ of 2 tool kg^–1 of C. To obtain a single (pH-dependent) stability constant for each metal-organic ligand complex, stoichiometries of 1:1:n metal/organic-ligand/OH^– complexes were determined from published linear relationships between pH and average equilibrium quotients normalized for complexing capacity of a polyfunctional complexer. Exchange in the exchanger phase included monovalent cations and anions to maintain phase electroneutrality. Model predictions of dissolved Zn, Cd, and Cu were calculated from relevant soil properties and macrochemical concentrations in each of 44 soil-solution samples collected from three manured field plots. Model-predicted Zn and Cd concentrations deviated from measured concentrations on the average 1.4- and 2-fold for measured concentration ranges of 120- and 34-fold (respectively). Copper was typically underpredicted by the model. Model-predicted speciation between the two principal dissolved metal species, free-ionic and DOC ligand-complexed, varied depending on soil solution macrochemistry. Soil solution chemical conditions ranged from pH 4.5 to 6.7, 30 to 260 g DOC m^–3, and electrical conductivities (EC) of 15 to 510 mS m^–1.

Contribution from the DLO-Institute for Soil Fertility Research.

Received for publication July 20, 1993.

This article has been cited by other articles:

				M. B. Benke, S. P. Indraratne, X. Hao, C. Chang, and T. B. Goh Trace Element Changes in Soil after Long-Term Cattle Manure Applications J. Environ. Qual., May 1, 2008; 37(3): 798 - 807. [Abstract] [Full Text] [PDF]

				C. J. Matocha, A. D. Karathanasis, S. Rakshit, and K. M. Wagner Reduction of Copper(II) by Iron(II) J. Environ. Qual., August 9, 2005; 34(5): 1539 - 1546. [Abstract] [Full Text] [PDF]

				M. Zhang, Z. He, D. V. Calvert, P. J. Stoffella, and X. Yang Surface Runoff Losses of Copper and Zinc in Sandy Soils J. Environ. Qual., May 1, 2003; 32(3): 909 - 915. [Abstract] [Full Text] [PDF]