Work

Micro/nanoplastics–metal(loid) co-exposure in rice: evidence, mechanisms, and food-safety implications

Year: 2026

Type: review

Abstract: Micro/nanoplastics (MNPs) and metal(loid)s frequently co-occur in rice agroecosystems, where legacy metal(loid) contamination and continuing plastic inputs may jointly threaten soil quality and rice safety. Co-exposure complicates risk assessment because rice responses cannot always be predicted from MNP-only or metal(loid)-only treatments. To address this, the review integrates mechanistic findings into a mixture- and context-dependent synthesis linking MNP traits and metal(loid) identity/speciation to soil-rhizosphere processes, plant uptake/partitioning, and grain food-safety outcomes. Metal(loid) exposure can disrupt growth by altering metal(loid) uptake, nutrient homeostasis, and redox regulation, whereas MNPs can modify root development, soil-root interfacial processes, and microbially mediated metal(loid) cycling. Consequently, co-exposure may generate responses with directions and magnitudes that depend on metal(loid) speciation, bioavailability, tissue partitioning, and plant performance, varying with metal(loid) identity, MNP properties, exposure dose, and environmental conditions. This review synthesizes current evidence on soil and rhizosphere processes, root uptake and internal transport, plant responses, and grain food-safety implications, with emphasis on Cd, inorganic As, Hg/MeHg, and Pb. It further identifies key evidence gaps, particularly the limited mature-grain and field-based evidence, and proposes integrated management strategies that reduce metal(loid) bioavailability and concentrations in mature rice grain, while avoiding increased MNP burdens, yield penalties, or deterioration in grain quality.

Source: Frontiers in Plant Science

DOI: 10.3389/fpls.2026.1963280