Current and Future Trends in Microplastics and Nanoplastics Alleviation from Croplands: A Threat to Agriculture, Finance, and Economy

Microplastics (MPs; < 5 mm) and Nanoplastics (NPs; 1 nm - 1 µm) are persistent contaminants in agricultural ecosystems and originate from plastic mulching, irrigation systems, packaging products, improper waste management, and atmospheric deposition. Their accumulation in soils is a concern for soil productivity, health, and safety and, by extension, food safety. The impacts of MPs and NPs on crop systems are reviewed with respect to the influence of polymer characteristics, size of the MPs and NPs, concentration of their exposure, and plant species. It also evaluates the potential for existing mitigation and remediation strategies. MPs and NPs can have an impact on seed germination, root growth, photosynthesis, nutrient assimilation, oxidation-reduction processes, and molecular responses in plants. The effects depend on the type of polymer, particle size, conditions, and concentrations. Smaller NPs tend to be more mobile and accessible to the cells, while MPs can impact plants via physical interference, soil structural modification, and microbial interactions. Additives and surface properties have a strong influence on toxicity; some polymers are more toxic than others. While these methods, such as microbial degradation, application of biochar, phytoremediation, and nanotechnology-based methods, are promising, it is hampered by cost, efficiency, and environmental restrictions when applied at a large scale. Emphasis needs to be placed on preventive systems, plastic management, and proven remediation systems. Long-term field studies, plant uptake mechanisms, toxicities of different polymer types, co-contaminant interactions, and food-chain transfer of plastics should be investigated in the future to provide sustainable solutions to plastic pollution in agriculture.