Long-Term Fate of Micro/Nanoplastics in Soil Systems and Their Impacts

Micro/nanoplastics are new global pollutants that have drawn major attention globally due to their potential to damage the ecosystem upon their persistence and accumulation. Micro/nanoplastics (MNPs) are inextricably released into the environment by terrestrial and land-based sources, particularly runoffs, and can be found in the majority of commonly used items in the form of primary microplastics or produced by the fragmentation of larger plastics as secondary microplastics. In recent decades, MNPs have been found to accumulate in the Earth’s environment, tissues, and gastrointestinal systems of animals including humans. These plastics are nonbiodegradable and their presence in air, soil, water, and food has led to ecotoxicological concerns and threats to biodiversity. Apart from this, due to their tiny size, the risks associated with their entry into the food chain are that they are taken up by plant roots and ingested by soil-dwelling fauna, causing morphological deformations, organ damage, and physiological malfunctions. Bioaccumulation of MNPs in plants has been identified to generate oxidative stress, which could alter gene expression and many metabolic pathways involved in plant growth, biomass production, and secondary metabolite synthesis. Many new methods for MNP analyses have been developed, while older technologies were repurposed that enabled the estimation in terms of scope and magnitude of plastic pollution up to nano-size range. Given the plastic threat’s pervasiveness and severity, this chapter provides a general overview of the occurrence, fate, and impacts of MNPs in soils, focusing on their ecological consequences.