Skip to main content

Research Repository

Advanced Search

Using isotopic dilution to assess chemical extraction of labile Ni, Cu, Zn, Cd and Pb in soils

Garforth, Judith M.; Bailey, Elizabeth H.; Tye, Andrew M.; Young, Scott D.; Lofts, Stephen

Authors

Judith M. Garforth

LIZ BAILEY LIZ.BAILEY@NOTTINGHAM.AC.UK
Professor of Environmental Geochemistry

Andrew M. Tye

Scott D. Young

Stephen Lofts



Abstract

Chemical extractants used to measure labile soil metal must ideally select for and solubilise the labile fraction, with minimal solubilisation of non-labile metal. We assessed four extractants (0.43 M HNO3, 0.43 M CH3COOH, 0.05 M Na2H2EDTA and 1 M CaCl2) against these requirements. For soils contaminated by contrasting sources, we compared isotopically exchangeable Ni, Cu, Zn, Cd and Pb (EValue, mg kg-1), with the concentrations of metal solubilised by the chemical extractants (MExt, mg kg-1). Crucially, we also determined isotopically exchangeable metal in the soil–extractant systems (EExt, mg kg-1). Thus ‘EExt - EValue’ quantifies the concentration of mobilised non-labile metal, while ‘EExt - MExt’ represents adsorbed labile metal in the presence of the extractant. Extraction with CaCl2 consistently underestimated EValue for Ni, Cu, Zn and Pb, while providing a reasonable estimate of EValue for Cd. In contrast, extraction with HNO3 both consistently mobilised non-labile metal and overestimated the EValue. Extraction with CH3COOH appeared to provide a good estimate of EValue for Cd; however, this was the net outcome of incomplete solubilisation of labile metal, and concurrent mobilisation of non-labile metal by the extractant (MExt < EExt > EValue). The Na2H2EDTA extractant mobilised some non-labile metal in three of the four soils, but consistently solubilised the entire labile fraction for all soil-metal combinations (MExt ≈ EExt). Comparison of EValue, MExt and EExt provides a rigorous means of assessing the underlying action of soil chemical extraction methods and could be used to refine long-standing soil extraction methodologies.

Citation

Garforth, J. M., Bailey, E. H., Tye, A. M., Young, S. D., & Lofts, S. (2016). Using isotopic dilution to assess chemical extraction of labile Ni, Cu, Zn, Cd and Pb in soils. Chemosphere, 155, https://doi.org/10.1016/j.chemosphere.2016.04.096

Journal Article Type Article
Acceptance Date Apr 24, 2016
Online Publication Date May 3, 2016
Publication Date Jul 1, 2016
Deposit Date Jul 20, 2016
Publicly Available Date Mar 29, 2024
Journal Chemosphere
Print ISSN 0045-6535
Electronic ISSN 1879-1298
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 155
DOI https://doi.org/10.1016/j.chemosphere.2016.04.096
Public URL https://nottingham-repository.worktribe.com/output/975918
Publisher URL http://www.sciencedirect.com/science/article/pii/S0045653516305860

Files





You might also like



Downloadable Citations