Quantification and Imaging of Polystyrene Micro‐ and Nanoplastics in Cress Stems ( Lepidium sativum ) via Raman Spectroscopy

Plastic pollution presents a pervasive environmental crisis with profound implications for ecosystems and human health. Among plastics, polystyrene is widely used and contributes significantly to micro‐ and nanoplastic pollution due to its fragmentation properties. While extensive studies have focused on aquatic systems, the impacts of polystyrene‐derived microplastics (MPs) and nanoplastics (NPs) on terrestrial plants remain underexplored. This study investigates the uptake, distribution, and morphological effects of spherical polystyrene MPs and NPs on garden cress ( Lepidium sativum ), a model plant species. Using Raman spectroscopic imaging, an advanced, noninvasive technique providing molecular and spatial resolution, we quantified the presence and localization of MPs and NPs (3.0, 1.1, and 0.1 μm) within plant tissues. Results reveal that particle size significantly influences transport and accumulation: NPs (0.1 μm) exhibit higher penetration and account for up to 51% of the polystyrene‐positive Raman signal area within plant tissues, compared to 38% for 1.1 μm MPs and 21% for 3.0 μm MPs. Raman mapping confirmed polystyrene presence in vascular tissues, suggesting potential pathways for further transport. This study is the first engagement of Raman spectroscopy for characterizing MPs and NPs in terrestrial plant tissues, offering critical insights into their ecological interactions. Findings highlight risks associated with plastic contamination in soils, emphasizing the need for strategies to mitigate environmental plastic pollution and its integration into terrestrial food chains. These results underscore the necessity for interdisciplinary approaches to address the challenges posed by global plastic pollution.