Trending Physico-Chemical Characteristics of Microplastics (MPs) and Nano-plastics (NPs) in Different Physical Environments and Their Role in Various Emerging Environmental Issues: A Review

Abstract

Microplastics (MPs) and nanoplastics (NPs) have become pervasive pollutants with profound implications for environmental and human health, making it imperative to understand their characteristics in various ecosystems. This study investigates the major polymer types of MPs and NPs, their sources, shapes, and distribution across marine, inland water, groundwater, soil, and atmospheric systems. Polyethylene (PE) and polypropylene (PP) dominate in fibrous forms across most environments, including inland water, groundwater, and soil, due to inputs from packaging materials, fishing nets, consumer products, and personal care items. In marine environments, PE and PP primarily appear as fragments because of coastal waste inputs, riverine discharges, fishing activities, and floating debris degradation. Inland waters, groundwater, and soils mainly receive fiber-shaped PE and PP through domestic discharge, agricultural activities, and wastewater effluents. Atmospheric MPs and NPs are largely fibrous forms of PE, polyethylene terephthalate (PET), polyamide (PA), and polyvinyl chloride (PVC), primarily originating from synthetic textiles, clothing, and household plastic packaging. This review also explores the environmental fate, transport mechanisms, and toxicity of MPs and NPs, highlighting their roles in emerging issues like COVID-19 spread, climate change impacts, ocean carbon sequestration, sea ice melting, and greenhouse gas emissions. Representative models illustrate these dynamics, shedding light on their complex behaviours and critical interactions. While research on MPs and NPs is expanding, significant gaps persist in understanding their long-term impacts and environmental characteristics across environmental matrices. This review provides a comprehensive overview and knowledge to safeguard ecosystems and human health from the escalating plastic pollution crisis.

Keywords: Microplastics, Nanoplastics, Polymer characterization, Major sources, Environmental matrices, Emerging environmental issues