Effect of polyethylene terephthalate (PET) microplastics on radish and carrot growth, nutrient uptake, and physiological stress responses

The widespread use and improper disposal of plastics in the environment lead to microplastic (MP) pollution. Polyethylene terephthalate (PET) plastics are widely used as single-use plastics, and the mass use of these plastics is contaminating aquatic and terrestrial environments. The transportation of those plastic fragments on agricultural land increases the risk to crop production and food safety. Therefore, the study aimed to evaluate the effect of polyethylene terephthalate microplastics (PET-MPs) on plant growth, nutrient uptake, and physiological stress responses. A short-term effect of PET-MPs (0.1 g/L) on plant growth was assessed using radish (Raphanus sativus) and carrot (Daucus carota var. sativa) grown in half-strength Hoagland solution for one week. PET-MPs did not significantly affect plant biomass and nutrient uptake by plants. Micronutrients such as Cu, Fe, Mn, and Zn were mostly increased in roots and decreased in shoot samples of both plants with PET-MP treatment compared to the control. Although short-term exposure of plants to PET-MPs did not significantly affect plant biomass and nutrient uptake, a significant difference was observed in the physiological stress responses. Chlorophyll a and b contents were significantly (p < 0.05) decreased in radish leaves after PET-MP treatment. Malondialdehyde (MDA) content in the leaves of radish plants significantly increased, indicating that the plant was facing abiotic stress in PET-MP treatment. This study advances understanding of MP-induced phytotoxicity and highlights its potential implications for food safety in agroecosystems.