[Source and distribution characteristics of polycyclic aromatic hydrocarbons in agricultural soils in the Pearl River Delta].

260 samples of surface agricultural soils (0-20 cm depth) were collected in the typical areas of Pearl River Delta from October 2002 to November 2005. The concentrations of polycyclic aromatic hydrocarbons (16 US EPA priority PAHs) in the collected soil samples were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS). The results showed that the concentrations of Sigma PAHs in the collected soil samples ranged from 3.3 to 4,079.0 ng x g(-1) with the average concentration of 224.2 ng x g(-1). PAHs in the collected samples were dominated by its 3-ring and 4-ring members. There were the higher concentrations of Sigma PAHs in the collected samples of urban sites than those of remote sites. The concentrations of PAHs in the collected samples related to different land use types the order: vegetable soils > paddy soils > banana soils > orchard soils > sugarcane soils. According to the distributions of fluoranthene/pyrene, 2 + 3 ring and 4 ring PAHs in these regions, it is supposed that the major contribution to the pollution of PAHs in these typical areas might be the incomplete combustion of fossil fuel. Compared with those in other national or international regions, the concentrations of Sigma PAHs in these typical regions were moderate.