Aransiola, S.A2025-01-302025-01-302023Aransiola, S.A., Victor-Ekwebelem, M.O., Ajiboye, A.E., Zobeashia, S.L.T., Ijah, U.J.J. and Oyedele, O.J., 2023. Ecological Impacts and Toxicity of Micro-and Nanoplastics in Agroecosystem. In Micro and Nanoplastics in Soil: Threats to Plant-Based Food (pp. 221-236). Cham: Springer International Publishing.https://doi.org/10.10007/978-3-031-21195-9_10https://repository.uniabuja.edu.ng/handle/123456789/704Micro- and nanoplastics are fragments of small plastics that are of sizes 1–5000 microns and <1 μm and consist of carbon and hydrogen atoms chained together by polymer. Micro- and nanoplastics are environmental pollutants, and their degradation depends on the properties of plastics, soil type, environmental condition, and microbial community. Their presence in the agricultural system is an emerging concern, which is basically attributed to the ability of the plastics to penetrate the soil and contaminate the soil plants, and microflora and fauna which thereby affect the food chain and security. Micro- and nanoplastics pollution in agrosystems originates from human activities (agricultural practices and anthropogenic sources) and natural sources (atmospheric inputs and flooding). Micro- and nanoplastics contamination of soil plants alters the chemical, physical, and biological properties of the soil ecosystem due to increased adsorption capacity when in combination with another organic contaminant. In agricultural ecosystems, micro- and nanoplastics affect soil microbial activity, microbial biomass, functional diversity, and the cycling process of plant nutrient elements in the soil, which have an indirect effect on plant seed germination and growth. When ingested or in association with the soil biota, micro- and nanoplastics can influence the agro-functionality through effects on soil root-associated microbiome and root symbionts, soil structure, nutrient immobilization, contaminant adsorption, and diffusion which can directly impact the fertility of the agricultural soil, plant qualities, and its yield. Microplastics excessive accumulation can directly result in toxic risk effects, including the interruption of the nutrient transport system by the obstruction of the pores in the cell wall, alter the community diversity, activity of the soil biota, and inhibition of nitrification. Microplastics and nanoplastics contribute to a major distribution of toxic and harmful compounds to soil plants, soil fauna, and photosynthetic organisms.enBook chapter