[Vertical distribution of polycyclic aromatic hydrocarbons in abandoned vehicles dismantling area soil]

In order to study the contamination by the U. S. EPA 16 priority polycyclic aromatic hydrocarbons (PAHs) in the soil of the end-of-life vehicle dismantling area, soil samples with vertical depth of 0-1 000 cm were collected and analyzed. The concentrations of EPA 16 priority PAHs were determined in soils samples. The results showed that total concentrations of PAHs were 991 ng.g-1 in surficial samples, with the highest concentrations detected for pyrene, benzo [a]anthracene and fluorine, reaching 11 820, 1 234 and 1 083 ng.g-1, respectively. The soils with the depth range of 0-10 cm were heavily polluted by PAHs, and the soils in the depth range of 50-350 cm were moderately or slightly polluted by PAHs. It seems that there was no PAHs pollution when the soil depth was over 400 cm. However, it was noted that the total concentration of 7 carcinogenic PAHs including chrysene (Chr), benzo [a] anthracene (BaA), Benzene and (b) fluoranthene(BbF) , Benzene and (k) fluoranthene (BkF), Benzo [a] pyrene (BaP), Diphenyl and [a, h] anthracene(DahA) , Indene and [1,2,3-CD] pyrene (IcdP) was still as high as 34.15 ng.g-1 in soil with a depth of 850 cm. The contents of PAHs decreased sharply with the increase in vertical depth. Low-ring PAHs such as phenanthrene, Fluoranthene and acenaphthene became the priority compounds when the depth was over 300 cm. The ratios of Phe/Ant and Fla/Pyr demonstrated that the PAHs in the soil profiles could be primarily sourced from petroleum pollution.