Your browser has javascript turned off or blocked. This will lead to some parts of our website to not work properly or at all. Turn on javascript for best performance.

The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Per Persson. Photo.

Per Persson

Director

Per Persson. Photo.

XAS study of iron speciation in soils and waters from a boreal catchment

Author

  • Anneli Sundman
  • Torbjorn Karlsson
  • Hjalmar Laudon
  • Per Persson

Summary, in English

Iron (Fe) is a key element, strongly influencing the biogeochemistry of soils, sediments and waters, but the knowledge about the variety of Fe species present in these systems is still limited. In this work we have used X-ray absorption spectroscopy (XAS) to study the speciation of Fe in soils and waters from a boreal catchment in northern Sweden. The aim was to better understand the controls of Fe speciation across different, but adjacent landscape elements including soil, soil solution, groundwater and stream water draining catchments with contrasting land characteristics. Our results showed that all samples contained mixtures of Fe(II) and Fe(III). The soils consisted of Fe phyllosilicates, Fe (hydr) oxides and Fe complexed by natural organic matter (NOM). All aqueous samples contained Fe(II)- and Fe(III)-NOM complexes, often in combination with Fe(III) (hydr) oxides that were associated with NOM. The variation in contribution from Fe-NOM and Fe (hydr) oxides was controlled by pH and total concentrations of NOM. The XAS spectra suggested formation of mononuclear Fe-NOM complexes consisting of chelate ring structures, but it could not be determined whether they originated solely from Fe(III)- or from a mixture of Fe(II)/Fe(III)-NOM complexes. Our collective results showed that the Fe speciation was highly variable across the different landscape elements and streams. This variation was manifested both in the distribution between mononuclear Fe-NOM complexes and Fe (hydr) oxides associated with NOM and between Fe(II) and Fe(III). These results highlight the complexity of Fe speciation in natural environmental systems and thus the challenges in interpreting Fe reactivity. (C) 2013 Elsevier B.V. All rights reserved.

Department/s

  • Centre for Environmental and Climate Science (CEC)
  • BECC - Biodiversity and Ecosystem services in a Changing Climate

Publishing year

2014

Language

English

Pages

93-102

Publication/Series

Chemical Geology

Volume

364

Document type

Journal article

Publisher

Elsevier

Topic

  • Earth and Related Environmental Sciences

Keywords

  • Fe speciation
  • XAS
  • Stream water
  • Soil solutions
  • Ground water
  • Krycklan
  • catchment

Status

Published

Project

  • MICCS - Molecular Interactions Controlling soil Carbon Sequestration

ISBN/ISSN/Other

  • ISSN: 0009-2541