Radiocesium adsorption-desorption on soils and clay minerals as influenced by potassium activity ratio

The knowledge on radiocesium behavior in soils is important for devising effective strategies and techniques to minimize its transfer to plants. In the present investigation, adsorption-desorption of radiocesium in soils and clay minerals as influenced by activity ratio of potassium (ARK) was studied. Seventeen soils representing different soil orders and seven pure clay minerals representing distinct clay mineral groups were used for the present study. The data indicates that > 90% of 134Cs was adsorbed on soils and clays even under the influence of competing solutions like calcium chloride and potassium. On an average the adsorption of 134Cs were comparatively higher in soils with neutral to alkaline pH. In the presence of (K+) ion, and with the increase in K+ ion concentration, the 134Cs adsorption decreased in all soils. Amongst the clays, the adsorption was minimum for kaolinite and halloysite in ARK solution. The desorption studies using ARK shows that, in general with an increase in concentration of the extractants, the total Cs desorbed also increases. Desorption was maximum in laterite and red soils and amongst clays, kaolinites showed almost similar trend.