Microplastics in terrestrial ecosystems: sources, transport, fate, mitigation, and remediation strategies

Microplastic (MP) pollution has become a pervasive environmental issue, extending beyond marine ecosystems to impact terrestrial environments significantly. This review article comprehensively examines MPs' sources, transport, and fate in terrestrial environments. Primary MPs, designed for commercial use, and secondary MPs, resulting from macroplastic deterioration, originate from various urban, farming, and manufacturing-related activities. MP dynamics in soils involve physicochemical and biological interactions, influencing their distribution, movement, and deposition. Wind, water flow, and soil organisms can transport MPs through diverse landscapes. MP fate is characterized by its persistence, potential for bioaccumulation, and incomplete degradation through physical, chemical, and biological mechanisms. This persistence poses significant ecological and health risks, as MPs can affect soil structure, water retention, and organism health. Much research efforts have been dedicated to marine ecosystems, whereas comparatively less attention has been given to terrestrial environments. It is crucial to investigate the fate of MPs, their transport mechanisms, their influence on soil quality, polymer composition and morphologies, and various land-use types. Establishing standardized and harmonized methodologies for the analysis of MPs in soil-plant ecosystems is pivotal. To minimize MPs' negative impacts on the environment and human health, safe and sustainable plastics design should be implemented. This review aims to enrich the comprehension of MP behaviour in terrestrial environments while informing strategies for mitigating their adverse effects, emphasizing the need for interdisciplinary research and effective policy interventions. Future investigations should also evaluate the various relations of MPs with soil quality and their ecotoxicological effects on organisms within the framework of worldwide environmental alterations.