Transport of Microplastics from Municipal Solid Waste Landfills to Aquatic system: An Overview

Microplastics possess a significant threat to water resources as well as aquatic life and present a challenge in overall water resource management. Among a wide variety of entry routes available for microplastics from land to water bodies, municipal solid waste (MSW) landfills are suspected to be one of the important land-based sources (entry point) of microplastics affecting water quality. Few studies reported the presence of microplastic in the leachate obtained from municipal solid waste landfills corroborating that MSW landfills not only act as a sink of microplastic pollution but also act as a source. Microplastics from these leachates move to the soil system thereby affecting its quality and further migrate to aquatic systems. This movement of microplastic from leachate to aquatic system not only deteriorate the water quality but also highlights the importance of land-based sources of microplastic. In this review, we focused on the role of landfills as a pathway for microplastics to water bodies. The main aims of this review the abundance and characteristics of microplastics in landfills and discuss the role of landfill age. Polyethylene in fragmented and fibrous form remains the predominant type and shape of microplastic in leachates. The shape, size, and abundance of microplastics in leachates vary with landfill age. Landfills also provide a favorable environment for microplastic degradation thereby turning macroplastics into tiny plastic pieces. The major type of degradation is oxidative degradation. Our review confirms that MSW landfills are indeed a source of microplastic and contribute to microplastic pollution in soil and aquatic systems.