Fate and Impacts of Microplastics in the Environment: Hydrosphere, Pedosphere, and Atmosphere

Plastic litter is on the rise where plastic waste ends up in undesignated areas such as the coastal shorelines, where the plastic is exposed to environmental conditions. As a result, the degradation and decomposition of plastics occur, leading to the formation of smaller fragments of plastics, termed microplastics. Microplastics have recently been considered as an emerging class of contaminants due to their ecotoxicological impact on the aquatic environment as well as soil matrix. Microplastics are of a size less than 5 mm and are produced from either a primary source (such as plastic pellets, and beads in makeup products) or a secondary source (such as the wear and tear of normal-use plastics and washing of clothes and textiles). Microplastic pollution is spread across the hydrosphere, pedosphere, and atmosphere, and these environmental zones are being studied for microplastic accumulation individually. However, there exists a source-sink dynamic between these environmental compartments. This study reviews the available literature on microplastic research and discusses the current state of research on the fate and transport of microplastic in the hydrosphere, pedosphere, and atmosphere, explores the ecotoxicological impact of microplastics on aquatic and soil communities, and provides prospective future research directions and plastic waste management strategies to control microplastic pollution. While the fate of microplastics in the hydrosphere is well-documented and researched, studies on understanding the transport mechanism of microplastics in the pedosphere and atmosphere remain poorly understood.