Microplastic pollution in the street dust of Delhi: a study on seasonal variations

Microplastic (MPs) pollution is a serious environmental issue, particularly in heavily polluted cities of India. Despite its relevance, comprehensive studies on MPs contamination in street dust are lacking. This primary study aims to address this gap by investigating MPs in street dust across various areas of Delhi during two different seasons. Samples were collected from four distinct locations of Delhi representing industrial, commercial, institutional, and landfill areas during the post-monsoon and summer seasons. The abundance of MPs during post-monsoon ranged from 4.44 ± 1.11 MPs 100 g^-1 in institutional areas to 18.88 ± 4.00 MPs 100 g^-1 in commercial areas. During summer, MPs concentrations increased, with landfill areas showing the highest counts at 116.66 ± 18.95 MPs 100 g^-1, and institutional areas the lowest at 35.55 ± 12.52 MPs 100 g^-1 of street dust, highlighting the strong influence of location-based and seasonal factors on MPs concentrations. FTIR analysis identified polymers such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), polystyrene (PS), and polyethylene terephthalate (PET) whereas scanning electron microscopy (SEM) revealed various degradation patterns on the surface of MPs indicative of prolonged environmental exposure and weathering processes. Fragments and fibres were the most common shapes reported in both seasons. Together, these findings reflect diverse and persistent anthropogenic sources driving urban MPs pollution, highlighting the cumulative impact of human activity, poor waste management practices, and environmental factors. Our results confirmed widespread evidence of MPs contamination in the street dust of Delhi, posing significant environmental and health risks. Immediate action and collaboration are needed to develop effective mitigation strategies. This study provides a foundation for future research and interventions to address MPs pollution in urban environments.