The potential of NAA and ICP-MS for determining soil dispersibility in relation to landslide incidents

Dispersive soils pose significant challenges due to their inherent tendency to rapidly respond to the presence of water, resulting in erosion and heightened susceptibility to landslides. The inclusion of sodium (Na) onto the surface of soil clay particles results in the attenuation of the electrochemical interactions between the dispersed soil, leading to the repulsion and subsequent migration of the clay particles away from one another. This study employed Neutron Activation Analysis (NAA) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to assess the Sodium Adsorption Ratio (SAR) and Exchangeable Sodium Percentage (ESP) as indicators of soil dispersibility. The results indicate that soils containing montmorillonite clay mineral exhibit greater values of SAR > 11 and ESP > 20 in comparison to soils containing other clay minerals i.e. kaolinite, illite, and vermiculite. The calculated SAR and ESP values obtained from both analyses demonstrate a notable agreement, indicating a positive correlation. In conclusion, it is apparent that both NAA and ICP-MS method has the capability to be applied for the purpose of predicting soil dispersibility in landslide-prone regions of Malaysia.