Microplastic Pollution: An In-depth Review of its Sources, Formation Mechanisms, Quantification Techniques, Environmental Impacts, Toxicological Effects and Remediation Strategies

Microplastic pollution has become a prevalent environmental issue, with particles smaller than 5 millimeters infiltrating virtually every ecosystem. This review provides a comprehensive analysis of microplastic sources, formation mechanisms, quantification techniques, environmental impacts, toxicological effects, and remediation strategies. Microplastics originate from both primary and secondary sources. Primary microplastics include deliberately manufactured particles such as microbeads and synthetic fibers from textiles. Secondary microplastics result from the degradation of larger plastic debris due to environmental factors such as UV radiation, mechanical abrasion, and chemical weathering. Land-based activities, including industrial processes, agriculture, and improper waste disposal, contribute tremendously to microplastic pollution, with land-based sources responsible for 80–90% of marine microplastic contamination. Accurate quantification of microplastics is imperative for assessing pollution levels and informing reduction strategies. Techniques such as Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM) are commonly used to identify and characterize microplastic particles. Microplastics cause remarkable threats to aquatic ecosystems. They can physically damage organisms through ingestion, resulting in blockages, malnutrition, and death. Moreover, microplastics serve as vectors for injurious chemicals, including persistent organic pollutants (POPs), which can leach into the environment and accumulate in the food chain. The presence of microplastics in marine environments disrupts habitats and affects biodiversity, with potential long-term consequences for ecosystem stability. The ingestion of microplastics has been linked to different adverse health effects in humans and wildlife. In humans, microplastics have been detected in biological samples like feces, saliva, blood, and placenta, raising concerns about potential health risks. Animal studies show that microplastics can cause oxidative stress, inflammation, and genotoxicity, even at low concentrations. Tackling microplastic pollution requires a multifaceted approach circumscribing prevention, removal, and mitigation. Microplastic pollution is a complex and escalating issue that necessitates concerted global efforts. Effectual management requires a combination of reducing plastic generation, improving waste management, advancing remediation technologies, and conducting further research to comprehend the full extent of microplastic impacts on health and ecosystems. Synergetic actions at the international, national, and local levels are crucial to mitigate the prevalent threat caused by microplastics and protect environmental and public health.