Assessment of co–contaminant effects on uranium and thorium speciation in freshwater using geochemical modelling

Lofts, Stephen ORCID: https://orcid.org/0000-0002-3627-851X; Fevrier, Laureline; Horemans, Nele; Gilbin, Rodolphe; Bruggeman, Christophe; Vandenhove, Hildegarde. 2015 Assessment of co–contaminant effects on uranium and thorium speciation in freshwater using geochemical modelling. Journal of Environmental Radioactivity, 149. 99-109. 10.1016/j.jenvrad.2015.07.011

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Official URL: http://dx.doi.org/10.1016/j.jenvrad.2015.07.011

Abstract/Summary

Speciation modelling of uranium (as uranyl) and thorium, in four freshwaters impacted by mining activities, was used to evaluate (i) the influence of the co–contaminants present on the predicted speciation, and (ii) the influence of using nine different model/database combinations on the predictions. Generally, co–contaminants were found to have no significant effects on speciation, with the exception of Fe(III) in one system, where formation of hydrous ferric oxide and adsorption of uranyl to its surface impacted the predicted speciation. Model and database choice on the other hand clearly influenced speciation prediction. Complexes with dissolved organic matter, which could be simulated by three of the nine model/database combinations, were predicted to be important in a slightly acidic, soft water. Model prediction of uranyl and thorium speciation needs to take account of database comprehensiveness and cohesiveness, including the capability of the model and database to simulate interactions with dissolved organic matter. Measurement of speciation in natural waters is needed to provide data that may be used to assess and improve model capabilities and to better constrain the type of predictive modelling work presented here.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.jenvrad.2015.07.011
UKCEH and CEH Sections/Science Areas:	Shore
ISSN:	0265-931X
Additional Keywords:	uranium, thorium, speciation, modelling, contaminants
NORA Subject Terms:	Ecology and Environment
Date made live:	02 Sep 2015 14:16 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/511318

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.jenvrad.2015.07.011

UKCEH and CEH Sections/Science Areas:

Shore

ISSN:

0265-931X

Additional Keywords:

uranium, thorium, speciation, modelling, contaminants

NORA Subject Terms:

Ecology and Environment