Micro- and nanoplastics across the plant-food-human continuum: Plant uptake, phytotoxicity, food safety, human-health implications, and mitigation strategies

Abstract

Micro- and nanoplastics (M/NPs) are accumulating in agricultural environments, raising concerns about crop performance, food quality, and dietary exposure. Building on earlier reviews of environmental occurrence, plant uptake, and phytotoxicity, this review critically evaluates evidence relevant to the environment-plant-food-human continuum and organizes it around exposure determinants, plant response pathways, and potential intervention points. We first examine how particle size, surface charge, polymer type, exposure route, and plant traits influence M/NP bioavailability, root and foliar uptake, and vascular transport. We then relate these processes to changes in seed germination, growth, photosynthesis, crop quality, and rhizosphere microbiota, and summarize the associated responses involving redox homeostasis, phenylpropanoid and cell-wall metabolism, carbohydrate and energy metabolism, hormone signaling, amino acid metabolism, nutrient homeostasis, and genomic integrity. Evidence for M/NP occurrence in edible tissues and trophic transfer is critically assessed; however, quantitative measurements of internal polymer burdens and plant-derived dietary exposure remain scarce, and adverse human-health implications are inferred mainly from cell and animal studies. Finally, mitigation approaches are evaluated at two levels: reducing plant exposure through rhizosphere management, soil amendments, nutrient regulation, agricultural source control, and ecological interception; and reducing household exposure through changes in drinking water, food preparation, textiles, and dietary practices. The available evidence remains constrained by non-standardized detection methods, simplified model particles, high exposure concentrations, and limited field and human validation. Future work should prioritize standardized measurements, environmentally realistic chronic exposures, and causal evaluation of transfer and mitigation across the plant-food-human pathway.