Occurrence, Distribution, and Abundance of Microplastics in the Rohtak Municipal Solid Waste Landfill

Objectives: To investigate the occurrence, distribution, morphological characteristics, and polymer composition of microplastics (MPs) in Rohtak municipal solid waste landfill underburdened soil samples. MPs were categorized based on size, shape, colour, and polymer type using microscopic examination and Fourier Transform Infrared Spectroscopy (FTIR). Method: Underburdened soil samples were collected from within 0-20 cm depth of the landfill site. Soil samples were filtered through a series of stainless-steel sieves of decreasing mesh size as followed 3000 μm, 2800 μm, 700 μm and 600 μm. MPs in the samples were visually examined, separated, and counted in 500g of total dry weight of underburdened soil. Further categorization was performed based on size, colour, and morphology under microscopic examination. Findings: The results revealed that smaller-sized MPs (750–600 µm) were more abundant than larger fractions, indicating progressive fragmentation of plastic debris into secondary MPs. Shape analysis showed the dominance of film-type particles, followed by fibres and fragments. Transparent particles were the most dominant colour category, indicating prolonged environmental weathering and degradation processes. FTIR analysis confirmed the presence of major polymers including polyethylene (HDPE and LDPE), polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS). The predominance of polyethylene and polypropylene reflected the extensive use of packaging and household plastic materials in municipal solid waste. Novelty: This study provides one of the limited investigations on microplastics contamination in landfill under burdened soil from India, particularly from the Rohtak Municipal Solid Waste Landfill. Unlike conventional landfill assessments that mainly focus on heavy metals and organic pollutants, the present work highlights the overlooked issue of MPs contamination in recovered landfill residues, thereby contributing valuable baseline data for sustainable landfill mining and waste management strategies.