Impact of erodent shape on microplastic breakdown during wind erosion

Microplastics in sedimentary environments can be subjected to mechanical abrasion when transported by the wind. The abrasion process changes the physical and chemical characteristics such as texture, size and shape, and breaks down the plastic, creating more microplastics and nanoplastics. To investigate the importance of erodent shape on the breakdown of microplastics during wind erosion a set of abrasion simulation experiments were designed with three different shapes of sediments (rounded, sub-angular and angular) and three sizes of polyethylene spheres (small, medium and large). The erodent effects were quantified by examining the particle velocity dynamics and changes in the physical-chemical properties of the microplastic surfaces. Preliminary results explain that the microplastics abraded with rounded-subangular sediments are exposed to higher particle velocities than the angular sediments in the experimental conditions. During the abrasion process the fragments that break away from the sediments adhere to the microplastic surfaces and change the chemical composition. The angular sediment produces the highest amount of fragments which adhere more quickly to the microplastic surfaces than the rounded-sub angular sediment. Larger microplastics tended to reduce their size with more hours of abrasion, and small-medium microplastics tended to retain their size. The results contribute towards understanding the origins and aerodynamic pathways of the microplastics, helping to explain possible sources of microplastic pollution in remote environments. Ongoing work will continue to investigate the erosion effects of different combinations of sediments and microplastic types. Also see: https://micro2024.sciencesconf.org/559073/document