In situ metal imaging and Zn ligand-speciation in a soil-dwelling sentinel: complementary electron microprobe and synchrotron microbeam X-ray analyses

A J Morgan, J F W Mosselmans, J M Charnock, A Bennett, C Winters, M O'Reilly, P Fisher, J Andre, M Turner, P Gunning, P Kille

Research output: Contribution to journalArticle

6 Citations (Scopus)


Understanding the relationships between accumulated metal speciation in cells and tissues of ecologically significant taxa such as earthworms will improve risk assessments. Synchrotron-based μ-focus X-ray spectroscopy was used to detect, localize, and determine ligand-speciation of Zn and Pb in thin sections of two epigeic earthworm species collected from a Pb/Zn-mine soil. The findings indicated that Zn and Pb partition predominantly as typical hard acids (i.e., strong affinities for O-donors) within liverlike chloragocytes. Moreover, Zn speciation was very similar in the chloragog and intestinal epithelia but differed subtly in the kidneylike nephridial tubules; neither Zn nor Pb was detectable in the ventral nerve cord. High resolution X-ray mapping of high pressure-frozen, ultrathin, freeze-substituted sections in a transmission electron microscope (TEM), combined with conventional TEM structural analysis, identified a new cell type packed with highly organized rough endoplasmic reticulum and containing deposits of Cd (codistributed with S); there was no evidence that these cells are major depositories of Zn or Pb. These data may be used in a systems biology approach to assist in the interpretation of metal-evoked perturbations in whole-worm transcriptome and metabolome profiles.

Original languageEnglish
Pages (from-to)1073-1081
Number of pages9
JournalEnvironmental Science & Technology
Issue number2
Publication statusPublished - 15 Jan 2013
Externally publishedYes


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