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

Due to the presence of highly pollutant industries in arid areas, many of the globe’s arid areas are exposed to severe local soil contamination events. In this work, the nature of solute and contaminant transport in the sandy terraces of an ephemeral stream that was exposed to a severe pollution event was examined. Here, the Ashalim Basin in the Judean Desert, Israel, is utilized as a case study. In order to shed new light on contaminant distribution along the soil profile and on transport mechanisms in arid environments, three complementary 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 solute release and transport; and (3) numerical simulation, used to define and understand the main associated processes. The study highlights the persistent nature of the pollutants in these natural settings, which dictates that they 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 (2019) was examined and compared to field measurements and numerical simulations and was found to be a useful tool for predicting the fate of the contaminants along the soil profile.