From Soil to Table: Pathways, Influencing Factors, and Human Health Risks of Micro- and Nanoplastic Uptake by Plants in Terrestrial Ecosystems

Micro- and nanoplastics (MNPs) are a new type of pollutant that are widely present in terrestrial ecosystems due to agricultural plastics, sludge use, deposition, and litter degradation. Plants can absorb them through the soil and atmosphere, with adverse effects on plant growth and development. Several studies have reported the effects of MNPs on plant physiology, biochemistry, and toxicity. However, the food chain risk of plant uptake of MNPs has not been systematically studied. This review synthesizes current research on plant MNP pollution, focusing on the uptake and transport mechanisms of MNPs by plants, influencing factors, and health hazards. The size, type, and surface charge characteristics of MNPs, as well as environmental conditions, are key factors affecting MNP absorption and accumulation in plants. Furthermore, when MNP-enriched plants are consumed by humans and animals, the accumulated MNPs can diffuse through the bloodstream to various organs, impairing physiological functions and causing a range of health problems. While a comprehensive, traceable investigation of the transmission of MNPs through the terrestrial food chain remains unconfirmed, health risk signals are unequivocal—dietary intake is the primary route of human exposure to MNPs, with direct evidence of their bioaccumulation in human tissues. Addressing this critical research gap, i.e., systematically verifying the full terrestrial food chain translocation of MNPs, is therefore pivotal for conducting robust and comprehensive assessments of the food safety and health risks posed by MNPs. This study analyzed a total of 154 literature sources, providing important theoretical insights into the absorption, transport, and accumulation of MNPs in plants, as well as the health risks associated with their transfer to humans through the food chain. It is expected to provide valuable reference for the research on the transfer of MNPs in the “soil-plant-human” chain.