Pollution characteristics of polycyclic aromatic hydrocarbons in water of Songhua River basin during the icebound season

The pollution characteristics of polycyclic aromatic hydrocarbons (PAHs) in surface water samples of the three major sections of the Songhua River Basin (the Nenjiang River, the Second Songhua River and the mainstream of the Songhua River) were studied. A total of 21 surface water samples were collected in icebound season in 2010 along the bank. The total concentrations of 15 species of PAHs ranged from 23.4 ng·L^-1 to 85.1 ng·L^-1, with an average concentration at (50.3±17) ng·L^-1, which was comparable with those of other rivers in China. PAHs had higher concentration in lower reaches of the river around neighboring cities, which maybe caused by municipal/industrial effluents of the cities along the bank. The sources of PAHs were further identified by principal component analysis (PCA), which indicated that the main source of PAHs was fossil fuel related combustion in Songhua River. The potential ecosystem risk assessment of individual PAHs was characterized by risk quotient (RQ). The results indicated that the ecological risk of high molecular weight PAHs was negligible and low molecular weight PAHs possessed greater ecological risk.