Porosities and Diffusivities of Some Nonsorbing Species in Crystalline Rocks

The diffusion of nonsorbing species in different rock materials and fissure coating materials has been studied on a laboratory scale. The nonsorbing species were iodide, Uranine, and Cr-EDTA. The results show that the effective diffusivity of iodide in rock materials with fissure coating material is of the same magnitude as or higher than the effective diffusivity of iodide in rock materials without fissure coating material. The results also show that the variations in the rock material are too large to give one value of the diffusivity in a rock material from a certain area. The estimated effective diffusivity of iodide in rock materials without fissure coating material was found to be in the range 1 x 10/sup -14/ m/sup 2//s to 70 x 10/sup -14/ m/sup 2//s.