Predicting cadmium adsorption on soils using WHAM VI.

Cadmium (Cd) adsorption on 14 non-calcareous New Jersey soils was investigated with a batch method. Both adsorption edge and isotherm experiments were conducted covering a wide range of soil composition, e.g. soil organic carbon (SOC) concentration ranging from 0.18% to 7.15%, and varying Cd concentrations and solution pH. The SOC and solution pH were the most important parameters controlling Cd partition equilibrium between soils and solutions in our experimental conditions. The Windermere humic aqueous model (WHAM) was used to calculate Cd adsorption on soils. The effect of solution chemistry (various pH and Cd concentrations) on Cd adsorption can be well accounted for by WHAM. For different soil compositions, SOC concentration is the most important parameter for Cd binding. Only a fraction of SOC, the so-called active organic carbon (AOC), is responsible for Cd binding. We found a linear relationship between SOC and AOC based on the adsorption edge data. The linear relationship was validated by the independent data sets: adsorption isotherm data, which presumably can be used to predict Cd partition equilibrium across a wide range of soil compositions. The modeling approach presented in this study helps to quantitatively predict Cd behavior in the environment.

[1]  I Thornton,et al.  The solid-solution partitioning of heavy metals (Cu, Zn, Cd, Pb) in upland soils of England and Wales. , 2003, Environmental pollution.

[2]  Lisa Axe,et al.  Modeling Cd and Zn Sorption to Hydrous Metal Oxides , 2000 .

[3]  E. Tipping.  WHAM—a chemical equilibrium model and computer code for waters, sediments, and soils incorporating a discrete site/electrostatic model of ion-binding by humic substances , 1994 .

[4]  D. Sparks,et al.  Predicting soil-water partition coefficients for cadmium , 1996 .

[5]  L. Weng,et al.  Contribution of individual sorbents to the control of heavy metal activity in sandy soil. , 2001, Environmental science & technology.

[6]  R. Comans,et al.  Leaching of heavy metals from contaminated soils: an experimental and modeling study. , 2004, Environmental science & technology.

[7]  J. Gustafsson,et al.  Modeling metal binding to soils: the role of natural organic matter. , 2003, Environmental science & technology.

[8]  R. Carignan,et al.  Trace metals in oxic lake sediments: possible adsorption onto iron oxyhydroxides , 1985 .

[9]  C. E. Cowan,et al.  Cadmium Sorption to Soil Separates Containing Layer Silicates and Iron and Aluminum Oxides , 1992 .

[10]  H. Allen,et al.  Effect of soil properties on copper release in soil solutions at low moisture content , 2006, Environmental toxicology and chemistry.

[11]  Herbert E. Allen,et al.  Solid-Solution Partitioning of Metals in Contaminated Soils: Dependence on pH, Total Metal Burden, and Organic Matter , 2000 .

[12]  D. Sparks,et al.  Zinc speciation in a smelter-contaminated soil profile using bulk and microspectroscopic techniques. , 2002, Environmental science & technology.

[13]  S. Sauvé,et al.  Solubility control of Cu, Zn, Cd and Pb in contaminated soils , 1997 .

[14]  M. Guo.  Soil Sampling and Methods of Analysis , 2009 .

[15]  S. Sauvé,et al.  Solid-solution partitioning of Cd, Cu, Ni, Pb, and Zn in the organic horizons of a forest soil. , 2003, Environmental science & technology.

[16]  M. Benedetti,et al.  Metal ions speciation in a soil and its solution: experimental data and model results , 2003 .

[17]  Michel Mench,et al.  Direct Determination of Lead Speciation in Contaminated Soils by EXAFS Spectroscopy , 1996 .

[18]  D. Sparks,et al.  Nickel sequestration in a kaolinite-humic acid complex. , 2003, Environmental science & technology.

[19]  I. Thornton,et al.  Trace Elements in Soils and Plants , 1980 .

[20]  L. Posthuma,et al.  Equilibrium partitioning of heavy metals in dutch field soils. II. Prediction of metal accumulation in earthworms , 1997 .

[21]  David G. Kinniburgh,et al.  Metal ion binding by natural organic matter: from the model to the field , 1997 .

[22]  D. Lumsdon.  Partitioning of organic carbon, aluminium and cadmium between solid and solution in soils: application of a mineral–humic particle additivity model , 2004 .

[23]  L. Weng,et al.  Understanding the effects of soil characteristics on phytotoxicity and bioavailability of nickel using speciation models. , 2004, Environmental science & technology.

[24]  E. Tipping.  Modelling Al competition for heavy metal binding by dissolved organic matter in soil and surface waters of acid and neutral pH , 2005 .

[25]  W. Peijnenburg,et al.  Correlation of the partitioning of dissolved organic matter fractions with the desorption of Cd, Cu, Ni, Pb and Zn from 18 Dutch soils. , 2002, Environment international.

[26]  E. Tipping.  Humic Ion-Binding Model VI: An Improved Description of the Interactions of Protons and Metal Ions with Humic Substances , 1998 .