Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons in Urban Road Dust

Abstract

In this study, a cost-effective and environmentally sustainable analytical 
method was developed for the detection and quantification of 16 polycyclic 
aromatic hydrocarbons (PAHs) identified under the US EPA Consent Decree in 
urban road dust. Methanol was employed both as the sole extraction solvent 
and as the organic phase in a methanol–water gradient high-performance liquid 
chromatography (HPLC) system, enabling efficient separation and analysis. 
Road dust samples were collected from diverse urban environments, including 
residential, industrial, and city center locations. Ultrasound-assisted 
extraction was applied to enhance PAH recovery. The measured concentrations 
of PAHs ranged from 77 to 1488.85 µg kg⁻¹ in city center dust, up to 2108 µg 
kg⁻¹ in residential areas, and between 138 and 1409 µg kg⁻¹ in industrial zones. 
The method achieved low detection (0.33–37.98 µg kg⁻¹) and quantification 
limits (0.99–22.87 µg kg⁻¹), along with satisfactory average recovery rates 
ranging from 69% to 88%. Precision was demonstrated through acceptable 
intra-day (78.91%–110.43%) and inter-day (75.30%–114.65%) variability. 
Health and ecological risks associated with the detected PAHs were assessed 
using toxicity equivalency factors (TEFs), hazard indices (HIs), incremental 
lifetime cancer risks (ILCRs), and ecological risk quotients (ERQs). While the 
PAHs in road dust were not found to pose significant human health risks, a 
moderate ecological risk was identified. Source apportionment analysis 
indicated that the predominant contributors to PAH contamination were 
combustion-related, specifically from gasoline and diesel fuel sources. Overall, 
the study demonstrates the potential of this simplified, green analytical 
approach for effective environmental monitoring of PAHs in urban road dust, 
especially in resource-limited settings.