The objectives of the proposed research are to provide both a qualitative and a quantitative evaluation of the different diffusion testing methods; and to determine the effect of cell size and test duration on the determination of effective diffusion coefficients. Comparisons of the measured effective diffusion coefficients will be made with respect to the type of test, the dimensions of the test cell, and the test duration. The effect of the use of retardation factors determined by both batch equilibrium and column test methods on the calculated effective diffusion coefficients will also be explored. This research should have a significant effect on the test procedures used to evaluate the potential for contamination due to diffusive transport through low-hydraulic conductivity waste containment barriers.
