Soil contamination in arid environments and assessment of remediation applying surface evaporation capacitor model; a case study from the Judean Desert, Israel

Abstract. Many of the globe arid areas are exposed to severe soil contamination events, due to the presence of highly pollutant industries in these regions. In this work a case study from the Ashalim basin, at the Judean desert, Israel was used to examine the nature of solutes and contaminants transport in sandy terraces of an ephemeral stream that was exposed to a severe pollution event. In order to to shed new light on contaminants distribution along the soil profile and transport mechanisms, in arid environments, three complimentary approaches were used: (1) Periodic on-site soil profile sampling, recording the annual solute transport dynamics; (2) Laboratory analyses and controlled experiments in a rain simulator, to characterize solutes release and transport; and (3) Numerical simulation was used to define and understand the main associated processes. The study highlights the stubborn nature of the pollutants in these natural setting that dictates they will remain near the soil surface, despite the presence of sporadic rain events. It was shown that a vertical circulation of the contaminates is occurring with soil wetting and drying cycles. The ‘surface evaporation capacitor’ concept of Or and Lehmann from 2019 was examined and compared to field measurements and numerical simulations, and found to be a useful tool to predict the fate of the contaminants along the soil profile.