Abundance and characteristics of microplastics in soil and leachate at different zones of unsanitary landfill

Landfills are increasingly acknowledged as significant sources of microplastic contamination. Landfills received huge amounts of plastic waste daily, which can degrade into microplastics over time and subsequently accumulate in soil or leach into surrounding environments through leachate. This study investigates the abundance and characteristics of microplastics (MPs) present in soil and leachate across various zones within a landfill., focusing on their size, shape, and polymer composition in young, middle-aged, and old landfill zones. The comprehensive approach involved sample collection, and laboratory analysis. Fourier-transform infrared (FTIR) spectroscopy identified the dominant polymers, and Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were used to explore factors influencing MP distribution and grouping patterns between soil and leachate samples. The results showed that the abundance of MPs in leachate was significantly lower in middle-aged landfills compared to young and old zones (P < 0.05). Fiber-shaped MPs were most common, with particle sizes ranging from 0.1 mm to 1.6 mm. FTIR spectroscopy identified polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS) as dominant polymer types. PCA indicated that landfill aging and environmental degradation influenced MP distribution, with HCA showing distinct patterns between soil and leachate. Smaller MPs were more mobile and found more often in leachate, while larger MPs were retained in soil. This study highlights the critical role landfills play as sources of MP pollution, emphasizing the need for improved waste management to reduce contamination and mitigate ecological and health risks. Effective strategies are essential to addressing the environmental impact of MPs in landfills.