Distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in urban rainfall runoff

Runoff samples were collected from traffic roads, campus, residential road and roof in a typical rain event. Polycyclic aromatic hydrocarbons (PAHs) in both dissolved and particle phases were investigated at impervious surfaces. The PAHs wash-off process at different monitoring sites was analyzed. The scatters of first flush were conducted in a method of fitting power function to quantitatively assess the magnitude of first flush effect (FFE). The sources of PAHs were identified using factor analysis. The results showed that PAHs concentrations in runoff samples varied from 317.21 ng·L^-1 to 10 364.3 ng·L^-1 with the maximal and minimal contents of PAHs found on Longwu Road and campus, respectively. The values of event mean concentration (EMC) varied considerably at different sampling sites. The concentration of washed-off pollutant generally decreased with runoff duration, which showed an obvious attenuation trend. The runoff process indicated the occurrence of FFE at different levels. PAHs mainly came from the incomplete combustion of fossil fuels, oil leakage and coking, and the contribution of each source was different in accordance with various surfaces.