Heavy metal contamination in street dust: source identification and health risk assessment in an urban Bangladeshi setting

This study investigates heavy metal (HM) contamination in street dust (SD) from 30 sites in Narayanganj, Bangladesh. Chromium (Cr) and copper (Cu) levels exceeded background values by five and ten times, respectively, and were among the highest reported worldwide when compared to urban datasets from South Asia, China, and other regions. Source apportionment using principal component analysis (PCA) and positive matrix factorization (PMF) indicates that manufacturing industries and traffic emissions are the primary potential sources. Müller’s geo-accumulation index classified copper as “moderately to strongly polluted” and cadmium as “strongly to extremely polluted.” Risk indices indicate that potential carcinogenic and non-carcinogenic risks were notably higher for children, mainly through ingestion. These findings underscore critical health risks in urban environments and necessitate targeted mitigation strategies for industrial emissions and traffic pollution.