Polyester Microplastic Fibers affect Soil Physical Properties and Erosion as a Function of Soil Type

Abstract. Microplastic is recognized as a factor of global change affecting many environmental compartments. Agricultural soils are likely hotspots of microplastic contamination in terrestrial ecosystems and are of particular concern due to their role in food production. Microplastic has already been shown to be able to affect soil properties, but its effect on different soil types is poorly understood. Moreover, no information is available on how the presence of this pollutant can affect soil water erosion processes, which are extremely important issues in many environments. In the light of this, we performed two experiments (a microcosm and a mesocosm study) to investigate how the presence of polyester microplastic fibers affects soil physical and hydrological parameters and processes such as aggregate formation and soil erosion in three different agricultural soil types. Our data show that the effects of polyester microplastic on soil physical parameters (including soil aggregation and erosion) are strongly dependent on soil type. We found that microplastic contamination can decrease the formation of new aggregates but at the same time increase their stability in water, with effects on soil erosion stronger as the intrinsic erodibility of soil increases. Overall, our results highlight the importance of broadly exploring soil properties such as texture, mineralogy, and organic carbon content to better understand how the various soil types respond to microplastic contamination.