A model system consisting of well-characterized quartz sand, negatively charged carboxyl-modified latex microspheres, and synthetic J- 13 groundwater was used as a first-step in defining limiting conditions for colloid transport at the proposed Yucca Mountain Repository for radioactive waste. Colloid (280-nm diameter) and tracer (bromide) transport was determined using column methods under steady-state flow conditions for both saturated and unsaturated moisture conditions. Experiments were conducted at three water contents (13%, 70%, and 100% saturated) and four ionic strengths (deionized water, and 0.1 x, 1x, and 10x the ionic strength of J-13 groundwater, which has an ionic strength of 0.0116). Colloid mobility in the 13% saturated columns was appreciably less than in the 70% and 100% saturated columns, whereas colloid mobility in the 70% and 100% saturated columns were quite similar. Ionic strength had a significant impact on colloid retention, becoming more pronounced in the drier systems. Colloids were mobile in deionized water and the 0.1x J-13 groundwater. Retention was approximately 20% in 1x J-13 groundwater and 100% in the 10x J-13 groundwater. Compared with the 70% and 100% saturated conditions, colloid mobility decreased for the 10% saturated condition, with greater than 50% retention for the 1x J-13 groundwater system. As observed for the 70% and 100% saturated conditions, colloids in the 10x J-13 solution were essentially immobile. Colloid mobility is greatly affected by the ionic strength of the soil solution and this effect is moisture saturation dependent.
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J.F. McCarthy and J.M. Zachara. Environ. Sci. Technol. 23, 496–502 (1989).
M.A. McGraw, Ph.D. Dissertation. University of California–Berkeley, Berkeley, CA (1996).
J.R. Nimmo and K.C. Akstin. Soil Sci. Amer. J. 52, 303–310 (1988).
J.R. Nimmo, J. Rubin, and D.P. Hammermeister. Water Resour. Res. 23, 124–134 (1987).
J.L. Conca and J. Wright. Proceedings of the 12th Annual AGU Hydrology Days Conference, Richland, WA (1992).
J.L. Conca. Tech. Rep. 3044-WBS184.108.40.206.1 (Los Alamos National Laboratory, Los Alamos, NM, 1993) pp. 28.
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Gamerdinger, A.P., Kaplan, D.I. & Kessler, J.H. Impact of Ionic Strength on Colloid Mobility in Saturated and Unsaturated Porous Media. MRS Online Proceedings Library 556, 737 (1998). https://doi.org/10.1557/PROC-556-737