Vertical Distribution of Typical Petroleum Pollutants in an Oilfield of Gudao, china

In oilfields, crude oil exploiting process led to heavy soil contamination with petroleum pollutants. In this work, ten soil profile samples were collected and analyzed with GC-MS method to investigate the vertical distribution of typical petroleum pollutants in an oilfield of Gudao Region. The results showed that the highest concentrations of the five typical petroleum pollutants appeared in the range of 0-40 cm depth, and then the concentrations of these pollutants gradually decreased with increasing soil depth below 40 cm. The peak concentrations of total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs) and sulfur were 33.84 g/kg, 4624.58 mu g/kg and 1298.50 mg/kg, respectively, all found in the 0-10 cm soil layer of the profile. The n-alkanes content of 88.10 mg/kg was highest at the 10-20 cm depth of the soil profile. The highest content of 3293.68 mu g/kg for BETX (Benzene, Toluene, Ethylbenzene and Xylenes) appeared at the 30-40 cm soil layer. The soil size and organic matter content were the probable factors affecting the vertical distribution of the pollutants. The results could provide basic data for pollution monitoring and soil remediation.