Microplastic Pollutants in Aquatic Ecosystems: Present and Future Challenges

Abstract

Microplastics (MPs), an emerging contaminant in aquatic environments, are the cause of ecological and climatic risk and have thus become a hot topic for the global scientific community [1]. of the plastic waste that appears in natural environments [2] can be categorized into four main classes: macroplastics (MPs > 25 mm), mesoplastics (5–25 mm), microplastics (0.1–5 mm), and nanoplastics (NPs < 100 nm). Generally, plastic products generated throughout the human-dominated era are regarded as a sink in aquatic environments [3,4]. Understanding the potential sources of MPs in both freshwater and marine environments, along with their types, activities, makeup, and prevalence, poses a significant obstacle for those involved in water resource management, planning, and envi ronmental advocacy. In developing countries (such as India, China, and other South Asian regions), millions of tons of single-use plastic materials are manufactured and disposed of annually, adjoining to the marine system through coastal regions and rivers and, thereby, affecting marine life [5,6]. It is highly likely that, due to anthropogenic disturbances and the excessive use of MP products, these artificial polymers accumulating in freshwater habitats are leading to devastating alterations in aquatic ecosystems. Research activities are predominantly concentrated on marine ecosystems, neglecting freshwater systems, especially rivers, despite an understanding that rivers and land areas are significant sources and pathways transporting microplastics into the oceans. A number of methods, tools, and techniques have been adopted to sample, isolate, characterize, quantify, and identify microplastics in water columns and benthic sediment but quantification techniques that are more accurate still need to be explored [7]. Recently, MPs have been identified in both drinking water and its sources of origin, prompting deliberation concerning the practical implications of these developments and potential risks to human health. The absence of a standardized procedure for identifying, extracting, and sampling these MPs renders the qualitative aspect of their occurrence uncertain, leaving a realm yet to be investigated by researchers working in this field.