Soil the silent sink: unveiling microplastics contamination across different land-use types in Delhi, India

Microplastics (MPs) contamination in soil is a growing environmental issue, particularly in heavily polluted urban areas like Delhi. This study investigated the presence of MPs across five distinct land-use categories: forest, residential, industrial, high-traffic, and agricultural zones. The findings revealed that the industrial area exhibited the highest abundance of MPs, with 105.56 ± 8.82 MPs per 100 g of soil, followed closely by high-traffic zones, agricultural areas, and residential neighbourhoods. In contrast, the forest area recorded the lowest levels, with 55.56 ± 24.04 MPs per 100 g of soil. Fourier Transform Infrared (FTIR) spectroscopy confirmed the presence of polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (PET) polymer types in soil samples collected from various locations. The detection of polymers such as PE, PS, and PET in the form of films and fibres is indicative of their widespread use in products like food packaging, shopping bags, bottled water, disposable plates, and Styrofoam products. The study found that MPs predominantly appeared as fragments, with films and fibres following, particularly within the size range of 100-500 μm, especially in industrial and residential areas. This research underscores significant variations in MPs contamination linked to land-use patterns and provides baseline data for the soils of Delhi. It emphasizes the necessity for ongoing research, as well as targeted initiatives in monitoring, management, and policy development concerning soil MPs pollution.