Speaker
Description
Microplastics are increasingly present in soils, including saline soils, due to agricultural practices, wastewater reuse, and improper waste disposal. While evaporation and salt crystallization in saline soils have been extensively studied (1,2,3), how microplastic contamination alters these processes in saline soils remains poorly understood. Here, we investigate the combined effects of salinity and microplastics on evaporation and salt crystallization in porous media using column-scale evaporation experiments and X-ray microtomography. Soil columns were packed with either pure sand or sand mixed with 5% (w/w) polyvinylchloride (PVC) microplastics and saturated with freshwater or NaCl solution. Evaporation and salt crystallization dynamics were quantified using mass loss measurements together with optical and thermal imaging, while pore-scale salt crystallization patterns were resolved using X-ray tomography. Our results indicate that salinity suppressed evaporation by approximately 25-30%, whereas the presence of PVC microplastics enhanced evaporation, resulting in substantially higher cumulative water loss. Thermal imaging revealed distinct surface responses: NaCl-treated columns developed salt crusts that reduced surface temperature variability, while PVC-NaCl columns exhibited lower mean surface temperatures but markedly higher spatial variability with persistent temperature anomalies during evaporation. Pore-scale observations demonstrated that microplastics altered crystallization patterns by redistributing salt deposition within the upper portion of the column. These findings show that microplastics fundamentally modify evaporation (3) and crystallization processes in saline soils, with implications for soil moisture dynamics, surface energy balance (4), and environmental monitoring strategies.
| References | 1. Shokri-Kuehni, S.M.S., Vetter, T., Webb, C., Shokri, N. (2017). New insights into saline water evaporation from porous media: Complex interaction between evaporation rates, precipitation and surface temperature. Geophys. Res. Lett., 44, 5504-5510, https://doi.org/10.1002/2017GL073337 2. Jannesarahmadi, S., Aminzadeh, M., Helmig, R., Or, D., Oesterle, B., Shokri, N. (2025). The Role of Wind Velocity in Saline Water Evaporation from Porous Media and Surface Salt Crystallization Dynamics, ACS Earth Space Chem, 9, 1938−1945, https://doi.org/10.1021/acsearthspacechem.5c00130 3. Jannesarahmadi, S.; Aminzadeh, M., Raga, R., Shokri, N. (2023). Effects of microplastics on evaporation dynamics in porous media, Chemosphere, 311, 137023, https://doi.org/10.1016/j.chemosphere.2022.137023 4. Aminzadeh, M., Kokate, T., Shokri, N. (2025). Microplastics in Sandy Soils: Alterations in Thermal Conductivity, Surface Albedo, and Temperature, Environ. Pollut., 372, 125956, https://doi.org/10.1016/j.envpol.2025.125956 |
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| Country | Germany |
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