Contamination of polycyclic aromatic hydrocarbons (PAHs) in urban soils in Beijing, China

Soil contamination with polycyclic aromatic hydrocarbons (PAHs) is an increasing problem in many countries, including China. An extensive and systematic survey has been undertaken to evaluate the contamination with PAHs of urban soils in Beijing, China. Soil samples were collected from campuses of universities, schools and kindergartens, public squares, fallow land and roadsides, and were analyzed for 16 PAHs by GC-MS. There was a high variability in the total PAHs (∑PAHs) concentrations, ranging from less than 366 to 27,825 ng g− 1. The highest ∑PAHs concentrations were found at roadsides and industrial sites. Soil organic carbon (SOC) is one of the important factors that can influence the concentrations of PAHs in soils. It was found that concentrations of ∑PAHs were significantly correlated with that of soil organic carbon. To trace the sources of PAHs, the ratios of phenanthrene to anthracene and fluoranthene to pyrene were used to identify pyrogenic and petrogenic sources, respectively. In most cases, PAHs in soils in urban areas of Beijing were pyrogenic. These sources included motor vehicle exhausts, industrial activities and coal burning. These data can be further used to assess the health risk associated with soils polluted with PAHs.