A review on microplastics in landfill leachate: formation, occurrence, detection, and removal techniques

Plastic is a widely used material that provides numerous benefits to modern society. A major portion of plastic waste (PW) makes its way to landfills. Thermal deterioration, biodegradation, mechanical abrasion, and chemical oxidation are the major processes contributing to the weathering (from macro to micro/nano) of plastic debris in landfills. Literature has shown that landfills serve as receptacles for the accumulation of PW. However, landfill leachate (LL) as a potential source of environmental microplastics (MPs) has not gained considerable attention. The high surface area and hydrophobicity of MPs enhance their ability to be ingested by living organisms and, at the same time, increase their susceptibility to the sorption of organic contaminants, heavy metals, and pathogens. This paper systematically reviews LL as a source of MPs to the environment, the formation of MPs from PW in landfills, associated environmental risks, and detection techniques of MPs in LL. The manuscript also addresses possible solutions, emphasising recent technical advances in removing MPs from landfills and the associated challenges. Future perspectives and potential management solutions are also discussed in this paper.