Information is presented on the nonequilibrium sorption of cobalt, cesium and strontium on Bandelier Tuff. Both adsorption and desorption were studied in the batch mode at 25 degree C with constant mixing. The reaction solutions consisted of 20 mg/L of stable cobalt, cesium or strontium with their radioactive tracers **6**0Co, **1**3**7Cs or **8**5Sr in 0. 01N CaCl//2 solution. Adsorption equilibrium occurs rapidly for strontium, somewhat more slowly for cesium, and very slowly for cobalt. The results of this study suggest that equilibrium models may be adequate to describe the movement of strontium in Bandelier Tuff under dynamic flow conditions. However, nonequilibrium models, in all probability, will be needed to describe the movement of cesium and cobalt under those same conditions.
