Modelling the complexation of Cd in soil solution at different temperatures using the UV-absorbance of dissolved organic matter

Cornu, Jean-Yves; Schneider, Arnaud; Jézéquel, Karine; Denaix, Laurence

doi:10.1016/j.geoderma.2011.01.005

Cited by 46 publications

(16 citation statements)

References 43 publications

(58 reference statements)

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“…Initially we looked for relationships with SUVA 254 values, given the promising results obtained by soil scientists working on Cu and Cd speciation in soil solutions. [17,18] However, plots of %aFA opt against SUVA 254 or the fluorescence index failed to yield useful relationships (see Figs S5, S6). Our interest then turned to the fluorescence spectrum, to determine if it could be used to estimate the proportion of DOM that is active in metal complexation.…”

Section: Optimisation Of Wham VI Predictionsmentioning

confidence: 99%

“…To be able to estimate this 'percentage active' DOM spectroscopically would be very useful. For example, the specific ultraviolet absorbance of the DOM (SUVA 254 ), a measure of the aromaticity of the organic matter, has been used to estimate the proportion of DOM that is present as HA or FA in solution and that participates in the complexation of Cu in reconstituted natural water samples [15,16] and in the complexation of Cu [17] and Cd [18,19] in soil extracts. A better a priori understanding of the quality of DOM in a given sample would alleviate the need to make assumptions about the activity of DOM and might reduce the discrepancies between predicted and measured free metal concentrations.…”

Section: Introductionmentioning

confidence: 99%

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Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality

et al. 2012

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Environmental context. To assess the risk posed by environmental contaminants such as metals, one needs to be able to identify the key chemical species that prevail in natural waters. One of the recognised stumbling blocks is the need to quantify the influence of heterogeneous dissolved organic matter (DOM). Here we explore the possibility of using the optical signature of DOM to determine its quality, to alleviate the need to make assumptions about its metal-binding properties and to improve the prediction of trace metal species distributions in natural waters.Abstract. To calculate metal speciation in natural waters, modellers must choose the proportion of dissolved organic matter (DOM) that is actively involved in metal complexation, defined here as the percentage of active fulvic acid (FA); to be able to estimate this proportion spectroscopically would be very useful. In the present study, we determine the free Cd 2þ , Cu 2þ , Ni 2þ and Zn 2þ concentrations in eight Canadian Shield lakes and compare these measured concentrations to those predicted by the Windermere Humic Aqueous Model (WHAM VI). For seven of the eight lakes, the measured proportions of Cd 2þ and Zn 2þ fall within the range of values predicted by WHAM; the measured proportion of Cu 2þ falls within this range for only half of the lakes sampled, whereas for Ni, WHAM systematically overestimated the proportion of Ni 2þ . With the aim of ascribing the differences between measured and modelled metal speciation to variations in DOM quality, the percentage of active FA needed to fit modelled and measured free metal concentrations was compared with the lake-to-lake variation in the spectroscopic quality of the DOM, as determined by absorbance and fluorescence measurements. Relationships between the percentage of active FA and DOM quality were apparent for Cd, Cu, Ni and Zn, suggesting the possibility of estimating the percentage of active FA spectroscopically and then using this information to refine model predictions. The relationships for Ni differed markedly from those observed for the other metals, suggesting that the DOM binding sites active in Cd, Cu and Zn complexation are different from those involved in Ni complexation. To our knowledge, this is the first time that such a distinction has been resolved in natural water samples.

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Section: Optimisation Of Wham VI Predictionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality

et al. 2012

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“…Otherwise, it is recommendable to directly measure these parameters from the soil to be characterized. The initial Cd 2+ concentration can be determined by specific electrode or by resin-based methods (Cornu et al 2009(Cornu et al , 2011Schneider et al 2009) while the buffer power for the free ion could be assessed by sorption/desorption experiments including the determination of the free ion fraction at equilibrium.…”

Section: Strong Complexation Kinetic Limitation and Low Complex Contrmentioning

confidence: 99%

“…Indeed, a large fraction of the soil Cd is generally adsorbed onto the solid phase including clay and organic matter (Mesquita and Silva 2002;Sauvé et al 2000a, b). In the soil solution, in addition to the free Cd 2+ ion, Cd also exists as complexes, mainly formed with soluble organic ligands (Cornu et al 2009(Cornu et al , 2011. The concentration of Cd 2+ at the root surface is governed by sorption and complexation reactions and by the transport of Cd toward the root surface by diffusion and mass flow (Schneider 2008;Sterckeman et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Ranking of mechanisms governing the phytoavailability of cadmium in agricultural soils using a mechanistic model

et al. 2015

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Aims The objective of this study was to rank the mechanisms influencing the phytoavailability of cadmium(Cd) in agricultural soils.Methods We developed a model that simulates the transport by diffusion and convection, the kinetics ofsorption and complexation in solution and the root uptake of Cd. The ranking of mechanisms was performed by simulating the Cd2+ uptake by 1 cm2 root for 30 days for French agricultural soil characteristics.Results The initial Cd2+ concentration was the most influential parameter followed by the soil buffer power for Cd2+ and by the soil water content and impedance factor. The Cd2+ was generally strongly depleted at theroot surface and the convection was almost negligible. In general, the Cd complex dissociation contributedlittle to the uptake due to a strong kinetics limitation. Conversely, the kinetics of sorption was little influential.Conclusions The initial concentration and diffusion of Cd2+ were the dominant processes governing the phytoavailability in non-polluted soils. A model considering only the transport and sorption of Cd2+ without kineticswould be adequate to predict the phytoavailability. The particular situations where these simplifications do nothold (relative error >10 %) corresponded to a high supply of labile Cd complex toward plant roots

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“…However, there is considerable controversy regarding the influence of DOM on metal solubility and uptake by plants. Some researchers have reported that DOM can form soluble metal-DOM complexes, and is preferentially adsorbed onto the soil surface in place of metals, which reduces the metal adsorption onto the soil, promoting metal phytoavailability when the soil pH is above a certain value [10,11]. However, other researchers have reported that DOM contains mono-or multidentate functional groups that exhibit the capability to form strong heavy metal complexes.…”

mentioning

confidence: 99%

Influence of Dissolved Organic Matter on Cd Speciation in Rhizosphere Soil Solution and Phytoextraction by Sedum alfredii and Sedum sarmentosum

Zeng

Lian

2015

Pol. J. Environ. Stud.

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Modelling the complexation of Cd in soil solution at different temperatures using the UV-absorbance of dissolved organic matter

Cited by 46 publications

References 43 publications

Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality

Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality

Ranking of mechanisms governing the phytoavailability of cadmium in agricultural soils using a mechanistic model

Influence of Dissolved Organic Matter on Cd Speciation in Rhizosphere Soil Solution and Phytoextraction by Sedum alfredii and Sedum sarmentosum

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