Microplastics in Edible Plants: an Underestimated Risk in the Human Food Chain

Microplastics (MPs) and nanoplastics (NPs) have appeared as ubiquitous contaminants in terrestrial ecosystems, with growing evidence of their interaction with agricultural crops. Recent studies have proved that plants can absorb MPs, particularly NPs (<100 nm), through root tissues via apoplastic pathways or endocytosis. Once internalized, plastic particles can be translocated to stems, leaves, and even edible parts, raising concerns about human exposure through plant-based foods. Experimental data confirm the presence of MPs in a wide range of crops, including lettuce, wheat, rice, tomatoes, and herbs, especially when grown in soils amended with contaminated compost or irrigated with polluted water. In rice grains, concentrations of up to 3 µg/g have been reported, while vegetables such as carrots and spinach may have up to 700 particles/kg. Plants can absorb plastic particles directly from the air. Particles in the air can enter leaves through various pathways, such as through structures on the leaf surface called the stomata and through the cuticle. Stomata are small openings made of cells, and the cuticle is a membrane, covered in insoluble wax, that is well suited for absorbing microplastics. Although dietary exposure through vegetables is currently estimated to be lower than that from seafood or drinking water, daily intake from plant sources can still reach several hundred particles, particularly in urban or intensively farmed areas. The health implications of ingesting plastic-contaminated plant matter remain incompletely understood. However, growing concern stems from the ability of MPs to cross intestinal barriers, induce oxidative stress, and act as vectors for heavy metals and persistent organic pollutants. In vitro and in vivo studies further suggest potential inflammatory, immunotoxic, and endocrine-disrupting effects. Significant gaps in analytical methodologies, standardized detection protocols, and long-term toxicological data currently hinder comprehensive risk assessment. Nevertheless, the expanding body of scientific evidence underscores the need for stricter regulation of agricultural inputs, such as compost, fertilizers, and reclaimed water, and for a more thorough evaluation of human exposure via plant-derived foods. Addressing this emerging challenge will require interdisciplinary approaches that integrate environmental science, agronomy, toxicology, and nutrition. Supported by grants from by Next Generation EU in the framework of PRIN 2022, CUP I53D23004490006 (S.D.) References 1. Avellan, A., et al. (2021). Critical Review: Role of Inorganic Nanoparticle Properties on Their Foliar Uptake and in Planta Translocation. Environmental science & technology. 2. Zytowski E, et al. (2025). Uptake and translocation of nanoplastics in mono and dicot vegetables. Plant Cell Environ. 3. Khatoon, N., et al. (2025). Microplastics in Essential Food Commodities: A Systematic Review of identification, detection, contamination, and Health Implications (2017–2024). Food Reviews International.