Solubility and transport of Cr(III) in a historically contaminated soil – Evidence of a rapidly reacting dimeric Cr(III) organic matter complex

Abstract

Chromium is a common soil contaminant and, although it has been studied widely, questions about its speciation and dissolutions kinetics remain unanswered. We combined information from an irrigation experiment performed with intact soil columns with data from batch experiments to evaluate solubility and mobilization mechanisms of Cr(III) in a historically contaminated soil (>65 years). Particulate and colloidal Cr(III) forms dominated transport in this soil, but their concentrations were independent of irrigation intensity (2-20 mm h(-1)). Extended X-ray absorption fine structure (EXAFS) measurements indicated that Cr(III) associated with colloids and particles, and with the solid phase, mainly existed as dimeric hydrolyzed Cr(III) bound to natural organic matter. Dissolution kinetics of this species were fast (<= 1 day) at low pH (<3) and slightly slower (<= 5 days) at neutral pH. Furthermore, it proved possible to describe the solubility of the dimeric Cr(III) organic matter complex with a geochemical equilibrium model using only generic binding parameters, opening the way for use of geochemical models in risk assessments of Cr(III)-contaminated sites. (C) 2017 The Authors. Published by Elsevier Ltd.

Keywords

Dimeric Cr(III) organic matter complex; EXAFS; Geochemical modeling; Dissolution kinetics; Irrigation experiment; Intact soil columns

Published in

Chemosphere
2017, volume: 189, pages: 709-716
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

SLU Authors

• Cornelis, Geert

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Löv, Åsa

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Sjöstedt, Carin

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Larsbo, Mats

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Persson, Ingmar

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

• Gustafsson, Jon-Petter

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Berggren Kleja, Dan

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    
  • Swedish Geotechnical Institute (SGI)

UKÄ Subject classification

Geochemistry

Publication identifier

• DOI: https://doi.org/10.1016/j.chemosphere.2017.09.088

Permanent link to this page (URI)

https://res.slu.se/id/publ/93048