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 Google Scholar Google Scholar Articles by Holm, P. E. Articles by McGrath, S. P. Search for Related Content PubMed Articles by Holm, P. E. Articles by McGrath, S. P. Agricola Articles by Holm, P. E. Articles by McGrath, S. P.

Speciation of Cadmium and Zinc with Application to Soil Solutions

Inst. of Environ. Sci. and Eng., Technical Univ. of Denmark, Building 115, DK 2800 Lyngby, Denmark;

S. P. McGrath

Soil Sci. Dep., Inst. of Arable Crops Res., Rothamsted Exp. Stn., Harpenden, Herts AL5 2JQ, UK.

^* Corresponding author.

ABSTRACT

A two-part method has been developed for determination of Cd and Zn species in 50-mL soil solution samples containing low concentrations of Cd and Zn (1–10 µg Cd L^–1 and 50–1000 µg Zn L^–1). The method uses two cation exchange resins (Amberlite CG 120 and Chelex 100) in a batch-column-batch procedure and relies on analytical determinations of Cd and Zn by graphite furnace atomic absorption spectrophotometry. The first part (batch) of the method allows determination of free divalent Cd²⁺ and Zn²⁺. This part is experimentally sensitive to cation concentrations and ionic strength and these parameters should be controlled during the experimental procedures. However, it is shown that Cd and Zn concentrations and pH do not influence the method. Speciations performed on samples containing chloride and sulfate were in accordance with theoretical calculations. The second part (column-batch) of the method operationally separates the complexed fraction into labile complexes, slowly labile complexes, and stable complexes. Chloro complexes were identified as labile complexes, while EDTA complexes were identified as stable complexes. The method works well with relatively small volumes of sample solutions and at low metal concentrations and may be useful in characterization of Cd and Zn in soil solutions.