Occurrence, Human Health and 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 priority polycyclic aromatic 
hydrocarbons (PAHs) listed under the U.S. EPA Consent Decree in urban road dust. The 
approach employed methanol both as the extraction solvent and as the organic phase in 
a methanol–water gradient high-performance liquid chromatography (HPLC) system, 
eliminating the need for toxic solvents and minimizing environmental impact. Road dust 
samples were collected from various urban settings—including residential, industrial, and 
city center areas—and subjected to ultrasound-assisted extraction to enhance PAH 
recovery. PAH concentrations in the samples showed significant spatial variation, ranging 
from 77 to 1,488.85 µg kg⁻¹ in the city center, up to 2,108 µg kg⁻¹ in residential zones, 
and between 138 and 1,409 µg kg⁻¹ in industrial areas. The method demonstrated low 
limits of detection (LOD: 0.33–37.98 µg kg⁻¹) and quantification (LOQ: 0.99–22.87 µg 
kg⁻¹), along with satisfactory average recovery rates of 69% to 88%. Precision studies 
indicated acceptable intra-day and inter-day variability, ranging from 78.91% to 110.43% 
and 75.30% to 114.65%, respectively. Health risk assessments based on toxicity 
equivalency factors (TEFs), hazard indices (HI), and incremental lifetime cancer risks 
(ILCR) revealed that PAH levels in the road dust posed minimal carcinogenic or non
carcinogenic health risks to the exposed population. Source apportionment analysis 
suggested that vehicular emissions—particularly from gasoline and diesel combustion—
 were the dominant contributors to PAH contamination. This method not only proves to 
be an efficient and greener alternative for monitoring PAHs in urban environments but 
also holds strong potential for routine environmental assessment in regions affected by 
traffic-related pollution.