Distribution and characterizing sources of polycyclic aromatic hydrocarbons of surface water from Jialing River

Sixteen priority polycyclic aromatic hydrocarbons （PAHs） in surface water samples were analyzed by gas chromatograph-mass spectrometer （GC-MS） to study their distribution and characterizing sources. The water samples were collected from five sites （J1-J5） in the Jialing River of Chongqing downtown area from September 2009 to August 2010. The results demonstrate that the concentration of total PAHs in three samples upstream are relatively higher than those in other two sites downstream, with average concentration of total PAHs for each site ranging from 811.5 ng/L to 1585.8 ng/L. The 2, 3 and 4-ring PAHs for sampling stations account for 13.0%, 56.6% and 28.6%, respectively, in total PAHs. There are obvious tendencies of seasonal change for PAHs concentration in surface water. The PAHs concentration in April of wet season is 1 301.6 ng/L, which is 1.3 times the lowest amount of total PAHs in August of flood season. Ratios of specific PAH compounds were used to characterize the possible pollution sources. Experimental results indicate that the PAHs in surface water samples are primarily from pyrolytic PAHs because of factories along these sites, while the direct leakage of petroleum products may be significant for two sites, Jiahua Bridge （J4） and Huanghuayuan Bridge （J5）, because of the wharf boat nearby.