Aquatic Geochemistry

, Volume 21, Issue 2, pp 197–215

Biogeochemical Factors Affecting Rare Earth Element Distribution in Shallow Wetland Groundwater

  • Mélanie Davranche
  • Gérard Gruau
  • Aline Dia
  • Rémi Marsac
  • Mathieu Pédrot
  • Olivier Pourret
Original Paper

DOI: 10.1007/s10498-014-9247-6

Cite this article as:
Davranche, M., Gruau, G., Dia, A. et al. Aquat Geochem (2015) 21: 197. doi:10.1007/s10498-014-9247-6

Abstract

Wetlands are specific areas able to regulate metals mobility in the environment. Among metals, rare earth elements (REE) appear to be particularly interesting because of the information that could be provided by the REE patterns. Moreover, as REE are becoming a matter of great economic interest, their significant release into the environment may be expected over the next few decades. Wetlands would then play a key role in the regulation of their concentration in the environment. This review demonstrated that REE are released in wetland bound to colloidal organic matter. During the flood season, the released REE concentrations are largely higher than those released during the wet period. This solubilization is related to the organic matter desorption caused by the pH rise imposed by the reducing reactions. The resulting REE patterns depend on the heterogeneity of the humic acid (HA) binding sites and the presence of potential competitive cations, such as Fe(III) and Al(III). At high REE loading, REE are bound to HA carboxylic groups and the pattern exhibit a MREE downward concavity. At low loading, REE are bound to phenolic and chelate groups and the pattern exhibits a lanthanide contraction. At low loading, REE seem to act as cationic bridges between two organic molecules, whereas at high loading they seem to be engaged in strong multidentate bonding. Moreover, the REE patterns can be modified with the competitive cations amount and speciation. The prime factor governing all these processes is pH, which drives the organic colloid production, REE loading and solubility of competitive cations.

Keywords

Rare earth elements Wetland Organic matter Colloids Sorption Fe(III) Al(III) Competition 

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Mélanie Davranche
    • 1
  • Gérard Gruau
    • 1
  • Aline Dia
    • 1
  • Rémi Marsac
    • 1
    • 2
  • Mathieu Pédrot
    • 1
  • Olivier Pourret
    • 3
  1. 1.Géosciences Rennes UMR 6118, CNRSUniversité Rennes 1Rennes CedexFrance
  2. 2.Institute for Nuclear Waste DisposalKarlsruhe Institute for TechnologyKarlsruheGermany
  3. 3.Institut Polytechnique LaSalle BeauvaisBeauvais CedexFrance

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