Microplastics Across Environmental Pathways: Detection, Transformation, Human Exposure, and Emerging Biodegradation Strategies

Abstract

Microplastic pollution has emerged as one of the most complex and pervasive environmental challenges of the twenty-first century, transcending ecosystem boundaries and raising concerns about long-term ecological integrity and human health. Originally recognized as a marine contamination issue, microplastics are now understood to circulate across marine, freshwater, terrestrial, and atmospheric systems, ultimately intersecting with human food chains and industrial processes. This article presents an extensive and integrative examination of microplastics based strictly on existing scholarly literature, focusing on their environmental occurrence, analytical detection methods, physicochemical transformation, interaction with biological systems, and emerging remediation and biodegradation strategies. Particular attention is given to marine microplastics as contaminants, detection advances such as Nile Red staining, physicochemical surface modification processes, contamination of commercial table salts, and the implications of chronic dietary exposure in the context of global sodium consumption. The article further explores the role of waste management practices, mineral-industrial interfaces, soil and freshwater transport dynamics, and recent advances in microbial degradation of synthetic polymers. By synthesizing insights from environmental chemistry, materials science, toxicology, microbiology, and public health perspectives, this work highlights critical knowledge gaps, methodological uncertainties, and future research directions. The findings underscore that microplastic pollution is not a singular environmental problem but a systemic phenomenon requiring coordinated analytical, regulatory, and biotechnological responses. This comprehensive review aims to contribute a theoretically grounded and policy-relevant framework for understanding microplastics as persistent, evolving, and biologically interactive contaminants with far-reaching implications for future generations.