Reconciling laboratory and field exposure: Mechanistic and cross-omics links between micro- and nanoplastic uptake and food safety in crops

Microplastic (MP) and nanoplastic (NP) contamination of agricultural systems has shifted from an environmental monitoring issue to an emerging food-safety concern of global relevance. Particles have been detected in edible tissues of crops, including rice, lettuce, cucumber, tomato and strawberry, raising concerns about their entry into human diets. Published estimates of total human microplastic intake, which rest on limited and heterogeneous datasets and include drinking-water and inhalation routes, are in the order of 74,000 to 211,000 particles per person per year. Three limitations obstruct risk assessment. First, laboratory studies use particle concentrations exceeding field-relevant levels by one to three orders of magnitude. Second, uptake pathways from soil through vascular tissue to edible organs remain mechanistically incomplete. Third, transcriptomic, metabolomic, and proteomic datasets persist as disciplinary silos rather than integrated frameworks. This review addresses these gaps through cross-omics integration. We synthesize physicochemical and anatomical mechanisms governing MP/NP uptake and translocation across root, foliar, and vascular tissues, and critically compare laboratory exposures with field-measured concentrations. We evaluate dose-response nonlinearities and polymer-specific toxicity: evidence suggests polystyrene may accumulate in vascular tissue more persistently than polyethylene, though such differences are confounded by size, charge, ageing, and additives, and are not yet reflected in risk models. We propose mechanistically plausible but unvalidated links between molecular disruption and food-safety-relevant outcomes, including iron bioavailability, amino acid composition, and contaminant co-transport. Three priorities emerge: resolving the lab-to-field concentration gap, characterizing phytohormone-mediated responses, and conducting multi-season field validation to enable evidence-based soil quality standards.