STUDY OF THE KINETICS OF THE INTERACTION OF CS-137 AND SR-85 WITH SOILS USING A BATCH METHOD - METHODOLOGICAL PROBLEMS

Some methodological problems of the use of batch method for the study of the interaction of radionuclides with soils are analyzed. The uptak e of Cs-137 and Sr-85 from simulated soil solution on three samples of soil was studied as a function of composition of the solution, concen tration of stable cesium or strontium and contact time, using two expe rimental arrangements of batch method. Two mechanisms of the uptake we re examined: isotopic exchange with stable isotope in soil and sorptio n on soil. The data obtained were evaluated using K-d coefficient or L angmuir isotherm and six kinetic models based on different processes c ontrolling the kinetics. It has been found that the uptake can be quit e well characterized by at least one of the kinetic models. The effect s of the composition of soil solution and concentration of stable cesi um or strontium are examined and their significance is briefly discuss ed.