Microplastics as Emerging Environmental Pollutants: Implications for Ecosystems and Human Health

Abstract

Microplastics (plastic particles <5 mm) have emerged as a pervasive and persistent class of environmental pollutants, now detected in nearly all ecological compartments including marine, freshwater, terrestrial, and atmospheric systems. Their omnipresence reflects increasing plastic production, widespread use of synthetic materials, inefficient waste management, and continuous fragmentation of larger plastic debris. Unlike conventional chemical contaminants, microplastics represent a heterogeneous mixture of polymer types, sizes, shapes, and associated additives, posing complex ecological and toxicological challenges. The present paper provides a comprehensive synthesis of literature published between 2000 and 2023, examining the sources, environmental distribution, ecological impacts, and potential human health implications of microplastic pollution. Evidence indicates that microplastics are readily ingested by organisms across trophic levels, leading to physical damage, oxidative stress, inflammatory responses, altered metabolism, and reproductive impairments. Their role as vectors for toxic chemicals and microbial assemblages further enhances their ecological significance. Human exposure occurs primarily through ingestion of contaminated food and water and inhalation of airborne microfibres, with recent biomonitoring studies reporting the presence of microplastic particles in human blood and tissues. Although definitive causal links between microplastic exposure and human disease remain limited, mechanistic studies suggest plausible pathways involving inflammation, immune dysregulation, and endocrine disruption. This paper critically evaluates current evidence, identifies key methodological uncertainties, and proposes an integrative framework for future risk assessment. Given the persistent nature of microplastics and their growing global footprint, mitigation strategies emphasizing source reduction, improved waste management, and material innovation are urgently required. Strengthening scientific understanding through standardized methodologies and interdisciplinary research is essential to inform evidence-based environmental and public health policies.