Microplastics and Nanoplastics as Multidimensional Environmental Stressors: Sources, Transport Pathways, Ecotoxicological Impacts, and Emerging Biodegradation Strategies

Abstract

The exponential growth of plastic production over the past seven decades has resulted in the pervasive accumulation of plastic debris across marine, freshwater, terrestrial, and atmospheric environments. Among these pollutants, microplastics and nanoplastics have emerged as particularly complex and hazardous contaminants due to their small size, high surface-area-to-volume ratio, chemical persistence, and capacity to act as vectors for other environmental pollutants. This research article provides an integrated and theoretically expansive examination of microplastic and nanoplastic pollution, synthesizing evidence from marine, soil, atmospheric, and food web studies while critically analyzing their physicochemical properties, transport mechanisms, toxicological effects, and biodegradation pathways. Drawing strictly from the provided references, the article explores how microplastics originate from both primary and secondary sources, undergo fragmentation and weathering, and subsequently interact with biological systems at multiple trophic levels. Special emphasis is placed on their role as carriers of persistent organic pollutants, heavy metals, and microbial communities, thereby amplifying ecological and human health risks. Furthermore, the article critically evaluates current detection methodologies and remediation strategies, including microbial and genetically modified organism-based plastic degradation, with particular attention to polyethylene terephthalate and emerging biodegradable plastics. By elaborating theoretical frameworks, addressing counter-arguments, and identifying unresolved research gaps, this work contributes a comprehensive, publication-ready synthesis intended to inform future interdisciplinary research and policy development on plastic pollution management.