Solid waste: An overlooked source of microplastics to the environment

Microplastics pollution is one of the most pressing environmental problems of the 21st century. While microplastics are pervasive throughout various environmental compartments, research to date has primarily focused on marine systems. Land-based microplastics sources (e.g., solid waste) have received comparatively little attention, although they account for the main flow of microplastics into aquatic environments. Solid waste microplastics sources primarily include landfill refuse, sludge, and food waste. Microplastics in these waste streams can be associated with various micropollutants that can have deleterious impacts on ecosystem health as they enter the food chain. Thus, understanding the occurrence, fate, and degradation pathways of solid waste microplastics is essential to develop comprehensive control and mitigation strategies. This study critically reviewed these key aspects of microplastics in municipal solid waste landfill refuse, sewage sludge, and food waste, and identified the interconnections of these components in the proliferation of microplastics to the environment. Additionally, microplastics related laws and regulations and their relevance to solid waste microplastics mitigation are discussed. [Display omitted] •Solid waste contributes to the environmental microplastics pollution.•Solid waste microplastics vary in concentration, composition, size, and shape.•Landfill refuse, sludge/biosolids, and food waste are major microplastics source.•Microplastics in solid waste absorb contaminants and exacerbate the problem.•Emerging regulations can help minimize microplastics proliferation via solid waste.