Interactions of radioactive and stable cesium with hydroxy-interlayered vermiculite grains in soils of the Savannah River Site, South Carolina, USA
Sorption and fixation of Cs by the upland soils of the US Department of Energy's Savannah River Site (SRS) have been attributed to micaceous grains consisting mostly of hydroxy-interlayered vermiculite (HIV). Results of experiments to characterize SRS soil samples, to examine aspects of their radiocesium sorption, and to determine how much of their natural Cs is accessible for chemical extraction and isotope dilution are presented in support of mechanistic hypotheses to explain Cs sorption and fixation in HIV grains. The HIV is responsible for most of the soil cation exchange capacity, and concentrations of naturally occurring Cs, Rb, and K in soil samples are closely related to the concentration of HIV. Experiments with 137Cs to examine (1) sorption kinetics, (2) blocking of exchange sites with silver thiourea, and (3) susceptibility of sorbed 137Cs to chemical extraction, support the idea that added Cs is sorbed at different kinds of cation exchange sites in HIV grains. Sites highly selective for Cs but relatively few in number are inferred to exist in interlayer wedge zones within such grains. Little of the naturally occurring Cs in the soil samples was extractable by chemical agents that would remove Cs from ordinary cation-exchange sites and from within non-silicate soil components. Furthermore, most of the natural Cs was inaccessible for isotope dilution under slightly acidic conditions approximating the natural soil environment. These observations support the idea that most of the Cs in these soils has become effectively fixed in the narrower parts of interlayer wedge zones. Control of Cs uptake and fixation by highly Cs-selective interlayer wedge sites would account for the large distribution coefficients found for 137Cs at the low aqueous Cs concentrations typical of environmental systems and also for the relatively large concentrations of stable Cs in the SRS soils.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: 01 June 2014
More about this publication?
- The JOURNAL publishes articles of interest to the international community of clay scientists, including but not limited to areas in mineralogy, crystallography, geology, geochemistry, sedimentology, soil science, agronomy, physical chemistry, colloid chemistry, ceramics, petroleum engineering, foundry engineering, and soil mechanics. Clays and Clay Minerals exists to disseminate to its worldwide readership the most recent developments in all of these aspects of clay materials. Manuscripts are welcome from all countries.
Clays and Clay Minerals is the official publication of The Clay Minerals Society.
The Editor-in-Chief is Professor Joseph W. Stucki [email protected]
- Editorial Board
- Information for Authors
- Membership Information
- Annual Meeting of The Clay Minerals Society
- Ingenta Connect is not responsible for the content or availability of external websites