Linking dissolved organic matter composition to metal bioavailability in agricultural soils: effect of anionic surfactants

Hernandez-Soriano, M. C. and Jimenez-Lopez, J. C. (2015) Linking dissolved organic matter composition to metal bioavailability in agricultural soils: effect of anionic surfactants. Biogeosciences Discussions, 12 5697-5723. doi:10.5194/bgd-12-5697-2015


Author Hernandez-Soriano, M. C.
Jimenez-Lopez, J. C.
Title Linking dissolved organic matter composition to metal bioavailability in agricultural soils: effect of anionic surfactants
Journal name Biogeosciences Discussions   Check publisher's open access policy
ISSN 1810-6285
1810-6277
Publication date 2015-04-14
Year available 2015
Sub-type Article (original research)
DOI 10.5194/bgd-12-5697-2015
Open Access Status DOI
Volume 12
Start page 5697
End page 5723
Total pages 27
Place of publication Goettingen, Germany
Publisher Copernicus
Collection year 2016
Language eng
Abstract The bioavailability of metals in soil is only partially explained by their partition among the solid and aqueous phase and is more related to the characterization of their speciation in the soil solution. The organic ligands in solution that largely determine metal speciation involve complex mixtures and the characterization of fluorescence components of dissolved organic matter (DOM) can identify pools of molecules that participate in metal speciation, this being essential for risk assessment. The bioavailability of Cd, Cu, Pb and Zn in three agricultural soils was examined in the laboratory to recreate irrigation with greywater enriched in anionic surfactants (Aerosol 22 and Biopower). Field capacity and saturation regimes were considered for this study. Irrigation with aqueous solutions of the anionic surfactants increased total DOM concentrations and metals in the soil solution (Pb > Cu > Zn > Cd). Significant correlation (p < 0.05) between the readily available pool of metals with the concentration of DOM was determined for Cu (r = 0.67), Pb (r = 0.82) and Zn (r = 0.68). However, speciation analysis performed with the software WHAM indicated that mobilisation of DOM and metals into the soluble phase resulted in a low concentration of free ion activities and promoted the formation of metal-organo complexes. The characterization of fluorescence components revealed that DOM in soil solution from soils irrigated with Aerosol 22 was enriched in a reduced quinone-like and a humic-like component. Besides, fluorescence quenching provided further evidence of metal complexation with organic ligands in solution. Hence, metal mobilization in soil irrigated with surfactant enriched greywater occurs with solubilisation of high affinity organic ligands, which substantially decreases the potential risk of metal toxicity.
Keyword Dissolved organic matter
Spectrofluorometry
Bioavailability
Heavy metals
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Agriculture and Food Sciences
Official 2016 Collection
 
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Created: Wed, 29 Apr 2015, 13:27:32 EST by Maria Hernandez-soriano on behalf of School of Agriculture and Food Sciences