Redistribution of Cs 137 introduced into montmorillonite in association with organic matter coming from biomass composting

Abstract The adsorption and later bioavailability of 137 Cs from the system humic acid (HA)/humic acid like compounds (HALC) and montmorillonite was investigated. The setup of the experiments should approach as much as possible natural conditions when 137 Cs is introduced into soil with HALC from decomposed biomass. The significant differences were found in the trials containing various HA/HALC and also pure montmorillonite. The 137 Cs was more available when it reached soil in association with HALC originated from compost than when it was adsorbed on stable humic acids. Moreover, the long term interaction of 137 Cs with HALC led to decrease of 137 Cs adsorbed on montmorillonite and increase of its bioavailable fraction. UV–Vis spectrometry and infrared spectroscopy showed the clear difference between HA, fresh HALC and old HALC which could partially explain the different results.