Cesium in Fukushima Soils: Characterizing Site-Specific Adsorption on Illite Particles

Abstract

Cesium is the major persistent radioactive species that remains in natural soils following the Fukushima Daichii nuclear disaster of 2011. These soils are rich in phyllosilicate minerals like illite clays. This study aims to combine experimental data and model-driven inferences to examine how different binding sites on illite particles may control cesium adsorption. Experimental results collected from wet-chemical experiments and inductively coupled plasma mass-spectrometry (ICP-MS) analysis provide strong evidence that the predominance of adsorption sites has no temporal variability on time scales ranging from one day to roughly one month. However, there is some disagreement of model estimates and high-resolution imaging with respect to which sites in particular are responsible for controlling adsorption within this time horizon. The results presented herein offer valuable insights for designing future studies that seek to better constrain how adsorption of contaminants on clay minerals may evolve over time.