Micro and nano plastics (MNPs) in agricultural soils: challenges for food security and environmental health

Micro and nano plastics (MNPs) are emerging pollutants in agricultural systems that pose health concerns for the soil, crop production, and food safety. This review examined the origins of microplastics (MPs), their occurrence frequency, effects on crops, and various methods of mitigation available in the agricultural system. The literature was thoroughly analyzed using Scopus, Web of Science, and Google Scholar, focusing on relevant research on MPs/NPs, agriculture, degradation, and environmental effects. MNPs infiltrate agricultural soils via the decomposition of plastic mulch, irrigation with wastewater, application of biosolids, and air deposition. Concentrations fluctuate significantly, spanning from 100 to 10,000 particles per kilogram of soil. Prevalent polymers encompass polyethylene and polypropylene. These particles hinder nutrient absorption, photosynthesis, enzymatic functions, development, and productivity of the plant, particularly in crops such as wheat, lettuce, and maize. Oxidative stress and modifications in microbial populations have also been documented. Their durability poses enduring ecological hazards and potential trophic transmission. The prevalent occurrence of MNPs in agroecosystems jeopardizes food security and environmental integrity. This review also emphasizes the necessity for biodegradable alternatives, sustainable practices, and microbial biodegradation of plastic. HIGHLIGHTS: 1. MNPs were detected at 100-10,000 particles/kg in agricultural soil samples. 2. Polyethylene and polypropylene dominate plastic types found in crop fields. 3. MNPs reduce biomass and nutrient uptake in crop plants. 4. Biodegradable strategies align with the SDGs to mitigate the impact of plastic in farming.