Occurrence, distribution, and risk assessment of organophosphate esters in urban street dust in the central province of Henan, China

In this study, nine OPEs were measured in 60 street dust samples collected from the central province of Henan, China. The total concentrations of OPEs (∑9OPEs) in street dust range from 2.77 to 505 μg/kg (median 59.3 μg/kg). Chlorinated OPEs are dominant in street dust with median concentration of 33.5 μg/kg, followed by aryl OPEs (median 9.05 μg/kg), and alkyl OPEs (median 6.19 μg/kg). No significant correlations are found between ∑9OPEs and parameters, such as population (p = 0.931), population density (p = 0.602), car ownership (p = 0.618), and gross domestic product (p = 0.863). Principal component analysis (PCA) result reveals that road traffic could be a major source of OPEs in street dust because of their extensive use in various vehicles. The total average (median) and high-level exposure (95th percentile) of OPEs are 1.01 × 10−2, 7.17 × 10−2 ng/kg bw/d for adults and 6.03 × 10−2, 0.43 ng/kg bw/d for children, respectively. Hazard quotient (HQ) values are 5–6 orders of magnitude lower than the acceptable risk level (HQ < 0.1), indicating there is still a low risk to local residents at current levels.