Assessment of Microplastics and Heavy Metal Contamination in Urban Road Dust: A Case Study from Begusarai, Bihar

This study investigates the occurrence, distribution and abundance of microplastics (MPs) and potential health risks associated with heavy metals (HMs) in road dust from Begusarai, Bihar, India. Road dust samples were collected from 33 sites across five land-use zones: Silent, Traffic, Commercial, Industrial, and Residential. MPs were extracted using Fenton's reagent, characterized by stereomicroscopy and Raman spectroscopy, and quantified by abundance, morphology, size, color and polymer type. HMs (Co, Cr, Ni, Cd, Pb, Mn, Zn, Cu, Fe) were analyzed using microwave-assisted acid digestion and atomic absorption spectroscopy. The Silent Zone exhibited the highest average MPs load (48.3 ± 27.3 items/2g) followed by the Commercial and Traffic Zones. Fragments dominated the MP profile (59.4%), with fibers (37.5%) and pellets (3.1%) less abundant. Most MPs were < 500 µm in size and white or black in color. Polyethylene terephthalate, polyvinyl chloride and polyurethane were the most common polymers identified. Fe, Mn, and Zn were the most abundant HMs, with Zn showing the highest enrichment and contamination levels. Pollution indices (PLI, EF, Igeo, CF) indicated moderate to low contamination for most HMs, with Zn as the primary concern. Non-carcinogenic health risks were within acceptable limits, but carcinogenic risks, particularly from Cr exposure, exceeded safe thresholds for both children and adults. The findings highlight the need for integrated pollution control measures and provide a scientific basis for evidence-based regulations to mitigate environmental and public health risks associated with urban dust pollution in Begusarai and similar industrial regions.