Foliar implications of polystyrene nanoplastics on leafy vegetables and its ecological consequences

The rise of airborne micro-nanoplastics (MNPs) pollution poses a significant threat to agroecological systems. Despite this issue, there is a critical gap in our understanding of their specific effects on various leafy vegetable species. To address this, we conducted a controlled experiment applying Polystyrene Nanoplastics (PS-NPs) on four leafy vegetables: Brassica rapa var. chinensis, B. rapa var. parachinensis, Amaranthus viridis, and Allium tuberosum. Our results showed that PS-NPs tend to accumulate within the epidermal layers and cuticles of these vegetables, particularly around stomatal apertures. More PS-NPs were found on the adaxial and abaxial side of leaves, compared to the cross-section. The abundance of PS-NPs accumulations varied significantly among the studied species due to differences in leaf structure. Notably, leaves with trichomes trapped more PS-NPs particles. These accumulation significantly reduced chlorophyll content and photosynthetic rates, altering the growth and nutritional quality of the vegetables. Our findings reveal the ecological effects of PS-NPs on the nutrient content, phenotype, physiology, growth and biomass metrics of common leafy vegetables. This highlights the potential for PS-NPs accumulation in edible plant tissues, raising concerns about food security and human health.