Investigation of 85Sr adsorption on selected soils of different horizons

Studies on the mechanism of 90Sr migration in soil require many processes to be considered. One of the most important is sorption on the surface of mineral components of the soil. In this study adsorption of 85Sr on a variety of soil types from different horizons has been investigated. Adsorption isotherms show various affinities of 85Sr, depending on soil type and to a lesser extent the horizon. An important effect of pH was found with a maximum in the range 5–7. The influence of calcium ions on the extent of adsorption of 85Sr isotope on soil samples from surface horizons of four sites is presented. Depending on the soil type differing degrees of competitive adsorption of Sr and Ca were observed. Desorption of 85Sr by distilled water as well as Ca(NO3)2 solution was also examined. Both methods resulted in the removal of a considerable proportion of the adsorbed isotope from the soil. Additionally the kinetics of the desorption process were studied.