Colloids in Groundwater and their Influence on Migration of Trace Elements and Radionuclides

Review on subsurface colloids and colloid-associated contaminant transport in saturated porous media

“…The study of radionuclide migration through the subsurface is an important issue in the safety assessment of nuclear waste repositories or radionuclide migration at former nuclear test sites. A number of investigations suggest that colloids dispersed in the groundwater provide an additional phase for radionuclides and enhance the transport of radinuclides [5,6,67,[136][137][138][139][140][141][142][143][144][145][146]. Radionuclide elements, especially the actinides (e.g., U, Np, Pu, Am), have a strong tendency to undergo hydrolysis and to form colloidal particles by precipitation [65 -67,142,147,148].…”

The Sorption of 210Pb, 210Bi and 210Po on Montmorillonite: A Study with Emphasis on Reversibility Aspects and on the Effect of the Radioactive Decay of Adsorbed Nuclides

“…As postulated by Lieser et al [9], the solubilities of sparingly soluble oxides or hydroxides depend frequently on the composition and the pretreatment of the solid, the solubility of which is considered. In the sorption experiments, relatively high local concentrations of Bi and Po are present in the solution prior to uniform dilution and prior to the sorption step, thus favouring the formation of polynuclear complexes and/or the sorption on colloidal impurities in solution (see discussion in 3.1.).…”

“…Starik [8] pointed out that those colloids contain great numbers of radioactive atoms and may be formed at concentrations far below the solubility product. Lieser et al [9] mentioned that the solubilities of sparingly soluble oxides or hydroxides are frequently not well defined. They depend on the composition and the pretreatment of the solid, the solubility of which is considered.…”

Competitive effect of iron(III) on metal complexation by humic substances: Characterisation of ageing processes

“…The mobility of metals and radionuclides in geochemical systems is substantially determined by interaction with organic and inorganic colloids as part of the aqueous phase (Lieser et al, 1990;Dearlove et al, 1991;Kim et al, 1992) (we would normally put the "et al" in italics but it's up to you). In particular, the complexing ability of humic and fulvic acids (HA, FA) as major constituents of the dissolved organic carbon (DOC) can dominate the speciation of multivalent metals (Buffle, 1988;Choppin, 1992).…”